Document:

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                                                                    Exhibit 10.3
                                                      PA/NJ - Property Transfers

                         AGREEMENT OF PURCHASE AND SALE

                                     between

                 PRENTISS PROPERTIES ACQUISITION PARTNERS, L.P.,
                         a Delaware limited partnership

                                  ("PRENTISS")

                                       and

                     BRANDYWINE OPERATING PARTNERSHIP, L.P.,
                         a Delaware limited partnership

                                ("BRANDYWINE OP")

                                       and

                           BRANDYWINE GRANDE B, L.P.,
                         a Delaware limited partnership

                                  ("GRANDE B")
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                                TABLE OF CONTENTS

                                                                            Page

ARTICLE I. DEFINITIONS.........................................................1
   1.1   Definitions...........................................................1
ARTICLE II. PURCHASE AND SALE; DEPOSIT; PAYMENT OF PURCHASE PRICE;
STUDY PERIOD; CONVEYANCE SUBJECT TO EXISTING NOTES AND LIENS...................8
   2.1   Purchase and Sale.....................................................8
   2.2   Payment of Purchase Price; Conveyance Subject to Existing Notes and
         Liens.................................................................8
   2.3   Deposit...............................................................8
   2.4   Study Period..........................................................9
ARTICLE III. PRENTISS' REPRESENTATIONS AND WARRANTIES.........................14
   3.1   Organization and Power...............................................14
   3.2   Authorization, Execution and Disclosure..............................14
   3.3   Non-contravention....................................................14
   3.4   No Special Taxes.....................................................14
   3.5   Compliance with Existing Laws and Restrictive Covenants..............15
   3.6   Personal Property....................................................15
   3.7   Operating Agreements.................................................15
   3.8   Condemnation Proceedings; Roadways...................................15
   3.9   Actions or Proceedings...............................................15
   3.10     Bankruptcy........................................................16
   3.11     Hazardous Substances..............................................16
   3.12     Parties in Possession.............................................16
   3.13     Leases............................................................17
   3.14     Leased Property...................................................17
   3.15     No Unpaid Charges.................................................17
   3.16     Condition of Improvements.........................................17
   3.17     Access............................................................18
   3.18     No Commitments....................................................18
   3.19     Prentiss Is Not a "Foreign Person"................................18
   3.20     Leasing Commissions...............................................18
   3.21     Other Agreements..................................................18
   3.22     Existing Secured Indebtedness.....................................18
   3.23     Employment on "At-Will" Basis.....................................19
   3.24     Ground Lease......................................................19
   3.25     LIMITATIONS ON REPRESENTATIONS AND WARRANTIES.....................19
ARTICLE IV. BRANDYWINE OP'S REPRESENTATIONS AND WARRANTIES....................21
   4.1   Organization and Power...............................................21
   4.2   Non-contravention....................................................21
   4.3   Litigation...........................................................21
   4.4   Bankruptcy...........................................................21
   4.5   Authorization, Execution and Disclosure..............................21
ARTICLE V. CONDITIONS PRECEDENT...............................................22
   5.1   As to Brandywine OP's Obligations....................................22

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   5.2   As to Prentiss' Obligations..........................................23
   5.3   Lot 21 Property and Lot 27 Property..................................24
ARTICLE VI. COVENANTS OF PRENTISS.............................................24
   6.1   Operating Agreements.................................................24
   6.2   Warranties and Guaranties............................................25
   6.3   Insurance............................................................25
   6.4   Operation of Property Prior to Closing...............................25
   6.5   No Marketing.........................................................27
   6.6   Leased Property......................................................27
ARTICLE VII. CLOSING..........................................................27
   7.1   Closing..............................................................27
   7.2   Prentiss' Deliveries.................................................28
   7.3   Brandywine OP's Deliveries...........................................30
   7.4   Mutual Deliveries....................................................30
   7.5   Closing Costs........................................................31
   7.6   Revenue and Expense Allocations......................................31
   7.7   Delinquent Rents.....................................................32
   7.8   Costs Associated with Certain Leasing Activities.....................33
ARTICLE VIII. GENERAL PROVISIONS..............................................33
   8.1   Condemnation.........................................................33
   8.2   Risk of Loss.........................................................34
   8.3   Broker...............................................................34
   8.4   Bulk Sale............................................................35
ARTICLE IX. LIABILITY OF BRANDYWINE OP; INDEMNIFICATION BY PRENTISS;
DEFAULT; TERMINATION RIGHTS...................................................35
   9.1   Liability of Brandywine OP...........................................35
   9.2   Indemnification by Prentiss..........................................35
   9.3   Default by Prentiss/Failure of Conditions Precedent..................36
   9.4   Indemnification by Brandywine OP.....................................37
   9.5   Default by Brandywine OP/Failure of Conditions Precedent.............37
   9.6   Costs and Attorneys' Fees............................................38
   9.7   Limitation of Liability..............................................38
ARTICLE X. MISCELLANEOUS PROVISIONS...........................................38
   10.1     Completeness; Modification........................................38
   10.2     Assignments.......................................................38
   10.3     Successors and Assigns............................................38
   10.4     Days..............................................................38
   10.5     Governing Law.....................................................39
   10.6     Counterparts......................................................39
   10.7     Severability......................................................39
   10.8     Notices...........................................................39
   10.9     Escrow Agent......................................................40
   10.10    Incorporation by Reference........................................40
   10.11    Survival..........................................................41
   10.12    Further Assurances................................................41
   10.13    No Partnership....................................................41

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   10.14    Time of Essence...................................................41
   10.15    Signatory Exculpation.............................................41
   10.16    Rules of Construction.............................................42
   10.17    Like-Kind Exchange................................................42
   10.18    SEC Reporting (8-K) Requirements..................................42

EXHIBITS

Exhibit A -       Land
Exhibit B -       Description of Ground Leases
Exhibit C -       Tenant's Estoppel Certificate
Exhibit D -       Excluded Tangible Personal Property
Exhibit E -       Existing Notes and Existing Liens
Exhibit F -       Form of Lender Estoppel Certificate
Exhibit G -       Form of Agreement for Prentiss' Partnership Interests in the
                  Lot 21 Owner and the Lot 27 Owner

SCHEDULES

Schedule 3.7      Operating Agreements
Schedule 3.13     Rent Roll and Accounts Receivable Report
Schedule 3.20     Outstanding Leasing Commissions
Schedule 6.4(g)   Approved New Leases

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                         AGREEMENT OF PURCHASE AND SALE

         THIS AGREEMENT OF PURCHASE AND SALE (this "AGREEMENT") is made as of
this ____ day of March, 2001, between PRENTISS PROPERTIES ACQUISITION PARTNERS,
L.P., a Delaware limited partnership and/or assigns (collectively, "PRENTISS"),
and BRANDYWINE OPERATING PARTNERSHIP, L.P., a Delaware limited partnership
("BRANDYWINE OP") and BRANDYWINE GRANDE B, L.P., a Delaware limited partnership
("GRANDE B").

                             R E C I T A T I O N S:

         A. Prentiss is the owner of a fee estate in certain real properties
located in the Commonwealth of Pennsylvania and State of New Jersey, as more
particularly identified on EXHIBIT A-1, attached hereto and made a part hereof
for all purposes and the owner of a leasehold estate in certain real properties
located in the Commonwealth of Pennsylvania, as more particularly identified on
EXHIBIT A-2 hereto and made a part hereof for all purposes.

         B. Brandywine OP is desirous of acquiring such property from Prentiss
and Prentiss is desirous of conveying such property to Brandywine OP, for the
Purchase Price and upon the terms and conditions hereinafter set forth;
provided, Grande B shall be acquiring the portion of the real property
identified on EXHIBIT A-1 as Lake Center IV ("LAKE CENTER IV").

         NOW, THEREFORE, in consideration of the foregoing premises and in
consideration of the mutual covenants, promises and undertakings of the parties
hereinafter set forth, and for other good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged by the parties, it is
agreed:

                                   ARTICLE I.
                                   DEFINITIONS

1.1      DEFINITIONS.  The following terms shall have the indicated meanings:

             "ACT OF BANKRUPTCY" shall mean if a party hereto or any general
partner thereof shall (a) apply for or consent to the appointment of, or the
taking of possession by, a receiver, custodian, trustee or liquidator of itself
or of all or a substantial part of its property, (b) admit in writing its
inability to pay its debts as they become due, (c) make a general assignment for
the benefit of its creditors, (d) file a voluntary petition or commence a
voluntary case or proceeding under the Federal Bankruptcy Code (as now or
hereafter in effect), (e) be adjudicated a bankrupt or insolvent, (f) file a
petition seeking to take advantage of any other law relating to bankruptcy,
insolvency, reorganization, winding-up or composition or adjustment of debts,
(g) fail to controvert in a timely and appropriate manner, or acquiesce in
writing to, any petition filed against it in an involuntary case or proceeding
under the Federal Bankruptcy Code (as now or hereafter in effect), or (h) take
any corporate or partnership action for the purpose of effecting any of the
foregoing; or if a proceeding or case shall be commenced, without the
application or consent of a party hereto or any general partner thereof, in any
court of competent jurisdiction seeking (1) the liquidation, reorganization,
dissolution or winding-up, or the composition or

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readjustment of debts, of such party or general partner, (2) the appointment of
a receiver, custodian, trustee or liquidator for such party or general partner
or all or any substantial part of its assets, or (3) other similar relief under
any law relating to bankruptcy, insolvency, reorganization, winding-up or
composition or adjustment of debts, and such proceeding or case shall continue
undismissed for a period of ninety (90) consecutive days; or an order (including
an order for relief entered in an involuntary case under the Federal Bankruptcy
Code, as now or hereafter in effect) judgment or decree approving or ordering
any of the foregoing shall be entered and continue unstayed and in effect, for a
period of ninety (90) consecutive days.

             "APPLICABLE LAWS" shall mean any applicable building, zoning,
subdivision, environmental, health, safety or other governmental laws, statutes,
ordinances, resolutions, rules, codes, regulations, orders or determinations of
any Governmental Authority or of any insurance boards of underwriters (or other
body exercising similar functions), or any restrictive covenants or deed
restrictions affecting the Property or the ownership, operation, use,
maintenance or condition thereof.

             "ASSIGNMENT AND ASSUMPTION AGREEMENT" shall mean one or more
assignment and assumption agreements whereby, subject to the allocation
provisions in SECTION 7.8 hereof, (a) Prentiss (1) assigns and Brandywine OP
assumes the Assumed Operating Agreements, (2) assigns all of Prentiss' right,
title and interest in and to the Intangible Personal Property, to the extent
assignable, and (3) indemnifies, defends and holds Brandywine OP and its agents,
employees, officers, directors, shareholders and contractors harmless with
respect to all defaults, liabilities, claims, costs and expenses (including,
without limitation, reasonable attorneys' fees) relating to acts or omissions
accruing under the Assumed Operating Agreements before the Closing Date; and (b)
Brandywine OP indemnifies, defends and holds Prentiss harmless with respect to
all defaults, liabilities, claims, costs and expenses (including, without
limitation, reasonable attorneys' fees) relating to acts or omissions accruing
under the Assumed Operating Agreements after the Closing Date.

             "ASSIGNMENT OF GROUND LEASE" shall mean one or more assignment and
assumption agreements whereby (a) Prentiss assigns to Brandywine OP and
Brandywine OP assumes each Ground Lease, and (b) (1) Prentiss indemnifies,
defends and holds Brandywine OP harmless with respect to all liabilities,
claims, costs and expenses (including, without limitation, reasonable attorneys'
fees) arising out of defaults by Prentiss under each Ground Lease accruing or
occurring before the Closing Date, and (2) Brandywine OP indemnifies, defends
and holds Prentiss harmless with respect to all liabilities, claims, costs and
expenses (including, without limitation, reasonable attorneys' fees) arising out
of defaults by Brandywine OP accruing and occurring from and after the Closing
Date.

             "ASSIGNMENT OF LEASES" shall mean the assignment agreement, in
recordable form, whereby, subject to the allocation provisions in SECTION 7.8
hereof, (a) Prentiss (1) assigns and Brandywine OP assumes all of Prentiss'
right, title and interest in and to the Leases, and (2) indemnifies, defends and
holds Brandywine OP and its agents, employees, officers, directors, shareholders
and contractors harmless with respect to all defaults, liabilities, claims,
costs and

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expenses (including, without limitation, reasonable attorneys' fees) relating to
acts or omissions accruing under such Leases before the Closing Date; and (b)
Brandywine OP indemnifies, defends and holds Prentiss harmless with respect to
all defaults, liabilities, claims, costs and expenses (including, without
limitation, reasonable attorneys' fees) relating to acts or omissions accruing
under such Leases after the Closing Date.

             "ASSUMED OPERATING AGREEMENTS" shall mean the Operating Agreements
listed on SCHEDULE 3.7 hereto which are not to be terminated pursuant to the
last sentence of SECTION 3.7 hereof.

             "AUTHORIZATIONS" shall mean all licenses, permits and approvals
required by any governmental or quasi-governmental agency, body, department,
commission, board, bureau, instrumentality or officer, any owners association
created pursuant to deed restrictions affecting the Real Property or otherwise
appropriate with respect to the construction, ownership, operation, leasing,
maintenance, or use of the Property or any part thereof.

             "BILL OF SALE - PERSONAL PROPERTY" shall mean one or more bills of
sale conveying title to the Tangible Personal Property and the Intangible
Personal Property from Prentiss to Brandywine OP.

             "BRANDYWINE OP" shall mean Brandywine Operating Partnership, L.P.,
a Delaware limited partnership.

             "BRANDYWINE OP'S OBJECTIONS" shall mean the objections defined as
such in SECTION 2.4(d) hereof.

             "BRANDYWINE OP'S ORGANIZATIONAL DOCUMENTS" shall mean the
organizational documents and all amendments thereto of Brandywine OP.

             "CLOSING" shall mean the Closing of the purchase and sale of the
Property pursuant to this Agreement and shall be deemed to occur on the Closing
Date.

             "CLOSING DATE" shall mean the date on which the Closing occurs.

             "CLOSING DOCUMENTS" shall mean the documents defined as such in
SECTION 7.1 hereof.

             "DEEDS" shall mean those certain special warranty deeds conveying
title to each of the Parcels and subject only to Permitted Title Exceptions
affecting each such Parcel. If there is any difference between the description
of any portion of the Fee Estate Land constituting a Parcel as shown on EXHIBIT
A-1 attached hereto and the description of the applicable Parcel as shown on the
Survey, the description of the applicable Parcel to be contained in the
applicable Deed and the description of such Parcel set forth in the Title
Commitment shall conform to the description shown on the Survey.

             "DEPOSIT" shall mean all amounts deposited from time to time with
Escrow Agent by Brandywine OP pursuant to SECTION 2.3 hereof, plus all interest
or other earnings that may accrue thereon. All cash Deposits shall be invested
by Escrow Agent in a commercial bank or banks acceptable to Brandywine OP at
money market rates, or in such other investments as shall be approved in writing
by Prentiss and Brandywine OP. The Deposit shall be held and disbursed by Escrow
Agent in strict accordance with the terms and provisions of this Agreement.

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             "ENVIRONMENTAL DAMAGES" shall mean all third-party claims,
judgments, damages, losses, penalties, fines, liabilities (including, without
limitation, punitive damages and strict liability), encumbrances, liens, costs
and expenses of investigation and defense of any claim, whether or not such is
ultimately defeated, and of any settlement or judgment, of whatever kind or
nature, contingent or otherwise, matured or unmatured, including, without
limitation, attorneys' fees and disbursements and consultants' fees, any of
which arise as a result of the existence of Hazardous Materials upon, about or
beneath the Property or migrating or threatening to migrate from the Property,
or as a result of the existence of a violation of Environmental Requirements
pertaining to the Property.

             "ENVIRONMENTAL REQUIREMENTS" shall mean (i) all applicable
statutes, regulations, rules, policies, ordinances, codes, licenses, permits,
orders, approvals, plans, authorizations, and similar items, of all Governmental
Authorities, and (ii) all judicial, administrative and regulatory decrees,
judgments and orders, in each case of (i) and (ii) relating to the protection of
human health or the environment from Hazardous Materials and health and safety
of employees or the public from Hazardous Materials, including, without
limitation, all requirements thereof pertaining to reporting, licensing,
permitting, investigation and remediation of emissions, discharges, releases or
threatened releases of Hazardous Materials into the air, surface water,
groundwater or land, or relating to the manufacture, processing, distribution,
use, treatment, storage, disposal, transport or handling of Hazardous Materials.

             "ESCROW AGENT" shall mean Chicago Title Insurance Company, whose
address is 2001 Bryan Street, Suite 1700, Dallas, Texas 75201, Attention: Ellen
Schwab.

             "EXISTING LIENS" shall mean the deed(s) of trust, mortgage(s),
assignments of leases, indemnities, loan agreements and other security
instruments securing, evidencing or executed in connection with the Existing
Notes described on EXHIBIT E hereto.

             "EXISTING NOTES" shall mean the promissory notes described on
EXHIBIT E hereto.

             "FEE ESTATE LAND" shall mean those certain parcels of real estate
lying and being in the State of New Jersey and the Commonwealth of Pennsylvania,
as more particularly described on EXHIBIT A-1 attached hereto, together with all
easements, rights, privileges, remainders, reversions and appurtenances
thereunto belonging or in any way appertaining, and all of the estate, right,
title, interest, claim or demand whatsoever of Prentiss therein, in the streets
and ways adjacent thereto and in the beds thereof, either at law or in equity,
in possession or expectancy, now or hereafter acquired.

             "FIRPTA CERTIFICATE" shall mean the affidavit of Prentiss under
Section 1445 of the Internal Revenue Code, as amended, certifying that Prentiss
is not a foreign corporation, foreign partnership, foreign trust, foreign estate
or foreign person (as those terms are defined in the Internal Revenue Code and
regulations promulgated thereunder), in form and substance satisfactory to
Brandywine OP.

             "GOVERNMENTAL AUTHORITY" shall mean any federal, state, county,
municipal or other government or any governmental or quasi-governmental agency,
department, commission, board, bureau, officer or instrumentality, foreign or
domestic, or any of them.

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             "GROUND LEASE" shall mean each existing ground lease, and all
amendments thereto, under which Prentiss leases the Leasehold Estate Land, as
identified on EXHIBIT A-2 hereto.

             "GROUND LESSOR" shall mean each lessor under each Ground Lease.

             "HAZARDOUS MATERIALS" shall mean any chemical substance: (i) which
is or becomes defined as a "HAZARDOUS SUBSTANCE," "HAZARDOUS WASTE," "HAZARDOUS
MATERIAL," "POLLUTANT," "CONTAMINANT," or "TOXIC," "EXPLOSIVE," "CORROSIVE,"
"FLAMMABLE," "INFECTIOUS," "RADIOACTIVE," "CARCINOGENIC," or "MUTAGENIC"
material under any law, regulation, rule, order, or other authority of the
federal, state or local governments, or any agency, department, commission,
board, or instrumentality thereof, regarding the protection of human health or
the environment from such chemical substances including, but not limited to, the
following federal laws and their amendments, analogous state and local laws, and
any regulations promulgated thereunder: the Clean Air Act, the Clean Water Act,
the Oil Pollution Control Act, the Comprehensive Environmental Response,
Compensation, and Liability Act of 1986, the Emergency Planning and Community
Right to Know Act, the Solid Waste Disposal Act, the Resource Conservation and
Recovery Act, the Safe Drinking Water Act, the Federal Insecticide, Fungicide
and Rodenticide Act, and the Toxic Substances Control Act, including, without
limitation, asbestos and gasoline and other petroleum products (including crude
oil or any fraction thereof); (ii) without limitation, which contains gasoline,
diesel fuel or other petroleum hydrocarbons; (iii) without limitation, which
contains asbestos-containing materials or urea formaldehyde foam insulation; or
(iv) without limitation, radon gas; provided, however, the term "HAZARDOUS
MATERIALS" shall not include de minimis quantities of substances of kinds and in
amounts ordinarily and customarily used or stored in properties similar to the
Property for the purposes of cleaning or other maintenance or operations and
otherwise in compliance with Environmental Requirements.

             "IMPROVEMENTS" shall mean all buildings, improvements, fixtures and
other items of real estate located on the various Parcels and portions of the
Leasehold Estate Land which constitute the Land.

             "INSURANCE POLICIES" shall mean all policies of insurance
maintained by or on behalf of Prentiss pertaining to the Property, its
operation, or any part thereof.

             "INTANGIBLE PERSONAL PROPERTY" shall mean all intangible personal
property owned or possessed by Prentiss and used in connection with the
ownership, operation, leasing, occupancy or maintenance of the Property,
including, without limitation, (1) Prentiss' exclusive right to use any trade
names associated with the Property and all variations thereof (other than
variants of Prentiss' legal name, all rights to which shall be retained by
Prentiss), (2) the Authorizations, (3) escrow accounts (subject to the
provisions of SECTION 7.6 hereof), utility and development rights and
privileges, general intangibles, business records, plans and specifications
pertaining to the Real Property and the Personal Property, and (4) any unpaid
award for taking by condemnation or any damage to the Land by reason of a change
of grade or location of or access to any street or highway.

             "LAND" shall mean the Fee Estate Land and the Leasehold Estate
Land.
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             "LEASED PROPERTY" shall mean all leased items of personal property.

             "LEASEHOLD ESTATE LAND" shall mean each parcel of real estate which
is subject to a Ground Lease, situate in the Commonwealth of Pennsylvania, as
more particularly described on EXHIBIT A-2 attached hereto, together with all
easements, rights, privileges, remainders, reversions and appurtenances
thereunto belonging or in any way appertaining, and all of the estate, right,
title, interest, claim or demand whatsoever of Prentiss therein, in the streets
and ways adjacent thereto and in the beds thereof, either at law or in equity,
in possession or expectancy, now or hereafter acquired.

             "LEASES" shall mean all leases, tenancies and other rights of
occupancy or use for any portion of the Real Property and leasehold estate,
together with any and all amendments thereto; provided, the Leases shall not
include any Ground Lease.

             "OPERATING AGREEMENTS" shall mean all management, service, supply
and maintenance contracts, if any, in effect with respect to the Property and
all other contracts (other than the Leases) that affect the Property or are
otherwise related to the construction, ownership, operation, occupancy or
maintenance of the Property.

             "OWNER'S TITLE POLICY" shall mean an owner's policy of title
insurance for the Fee Estate Land and a leasehold policy of title insurance for
the Leasehold Estate Land issued to Brandywine OP by the Title Company, pursuant
to which the Title Company insures Brandywine OP's ownership of fee simple title
to the Fee Estate Land and leasehold title to the Leasehold Estate Land subject
only to Permitted Title Exceptions. The Owner's Title Policy shall insure
Brandywine OP in the aggregate amount of the Purchase Price and shall be
acceptable in form and substance to Brandywine OP. Brandywine OP may require
such deletions of standard exceptions and such title endorsements as are legally
available and customarily required by institutional investors purchasing
property comparable to the Property in each State where the Property is
situated. The description of the Land in the Owner's Title Policy shall be by
courses and distances or by reference to a legal, subdivided lot and shall be
identical to the description shown on the Survey.

             "PARCEL" shall mean each individual tract of the Fee Estate Land
described on EXHIBIT A-1 hereto.

             "PERMITTED TITLE EXCEPTIONS" shall mean each Ground Lease, the
Existing Liens, Existing Notes and those exceptions to title to the Real
Property that are satisfactory to Brandywine OP as determined pursuant to
SECTION 2.4(d) hereof.

             "PERSONAL PROPERTY" shall mean collectively the Tangible Personal
Property and the Intangible Personal Property.

             "PRENTISS' ORGANIZATIONAL DOCUMENTS" shall mean the organizational
documents and all amendments thereto of Prentiss.

             "PROPERTY" shall mean collectively the Real Property and the
Personal Property.

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             "PURCHASE PRICE" shall mean $58,842,621.00 payable in the manner
described in SECTION 2.2 hereof.

             "REAL PROPERTY" shall mean the Land and the Improvements.

             "RENT ROLL" shall have the meaning ascribed to such term in SECTION
2.4(b)(2) of this Agreement.

             "STUDY PERIOD" shall mean the period commencing on the date this
Agreement has been fully executed and delivered by all parties hereto, and
continuing through February 16, 2001. Except as expressly noted herein to the
contrary, time periods herein referred to shall mean the time periods as in
effect, from time to time, at Dallas, Texas.

             "SUBMISSION MATTERS" shall mean all items Prentiss is required to
deliver to Prentiss pursuant to SECTION 2.4(b) hereof.

             "SURVEY" shall mean the survey defined as such in and prepared
pursuant to SECTION 2.4(d) hereof.

             "TANGIBLE PERSONAL PROPERTY" shall mean the items of tangible
personal property consisting of all furniture, fixtures, equipment, machinery
and other personal property of every kind and nature located on or used or
useful in the ownership and operation of the Property and owned by Prentiss,
including, without limitation, Prentiss' interest as lessee with respect to any
such Tangible Personal Property, other than (a) the items of personal property
identified on EXHIBIT D hereto, and (b) the Leased Property, the title to which
personal property described in clauses (a) and (b) is not being transferred
pursuant to this Agreement.

             "TITLE COMMITMENT" shall mean the title commitment and exception
documents defined as such in SECTION 2.4(d) hereof.

             "TITLE COMPANY" shall mean Fidelity National Title Insurance
Company or other title insurance underwriter selected by Brandywine OP.

             "UCC REPORTS" shall mean the reports defined as such in SECTION
2.4(d) hereof.

             "UTILITIES" shall mean public sanitary and storm sewers, natural
gas (if any), telephone, public water facilities, electrical facilities and all
other utility facilities and services (if any) necessary or appropriate for the
operation and occupancy of the Property as an office building.

             "WARRANTIES AND GUARANTIES" shall mean all warranties and
guaranties relating to the Improvements, or the Tangible Personal Property or
any part thereof.

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                                  ARTICLE II.
             PURCHASE AND SALE; DEPOSIT; PAYMENT OF PURCHASE PRICE;
          STUDY PERIOD; CONVEYANCE SUBJECT TO EXISTING NOTES AND LIENS

         2.1 PURCHASE AND SALE. On the Closing Date, Prentiss agrees to sell and
Brandywine OP agrees to purchase the Property in accordance with and subject to
the other terms and conditions set forth herein.

         2.2 PAYMENT OF PURCHASE PRICE; CONVEYANCE SUBJECT TO EXISTING NOTES AND
LIENS. The Purchase Price shall be paid to Prentiss in the following manner:

             (a) Brandywine OP shall receive a credit against the Purchase Price
in an amount equal to the cash Deposit.

             (b) Brandywine OP shall accept the Property subject to, but in no
way assuming, the unpaid balances of the Existing Notes payable to the
lienholders described in EXHIBIT E hereto having approximate unpaid principal
balances in the amounts specified in EXHIBIT E, and subject to, but in no way
assuming the obligations contained in the Existing Liens. Brandywine OP shall
receive a credit against the Purchase Price in an amount equal to the
outstanding principal balance of the Existing Notes on the Closing Date.
Notwithstanding the foregoing, (i) to the extent that any of the Existing Notes
or Existing Liens (or the loan documents executed in connection therewith)
create personal liability for specified acts, omissions or occurrences (such
acts, omissions or occurrences being referred to as "CARVE-OUT ACTIVITIES") and
the associated personal liability being referred to as "CARVE-OUT LIABILITY"),
(A) Brandywine OP shall, if Closing occurs, be responsible for any such
Carve-Out Liability attributable to Carve-Out Activities accruing and occurring
from and after the Closing Date, and shall and does hereby indemnify and hold
Prentiss harmless with respect thereto, and (B) Prentiss shall and does hereby
indemnify and hold Brandywine OP harmless with respect to Carve-Out Liability
attributable to Carve-Out Activities accruing or occurring prior to the Closing
Date. If permitted by any holder of an Existing Note, Prentiss shall be released
from all Carve-Out Liability under such Existing Note and Existing Liens
securing payment of such existing Note, and Brandywine OP shall execute such
documents as the holder of any such Existing Note may reasonably require to
evidence the assumption by Brandywine OP of the Carve-Out Liability attributable
to Carve-Out Activities of Brandywine OP accruing and occurring from and after
the Closing Date. The provisions of this SECTION 2.2(b) shall survive the
Closing.

             (c) Brandywine OP shall pay the amount by which the Purchase Price
exceeds the sum of (a) the cash Deposit, plus (b) the outstanding principal
balance of the Existing Notes on the Closing Date, as adjusted in the manner
specified in ARTICLE VII and as set forth below, to Prentiss at Closing by
making a wire transfer of immediately available funds to the account of
Prentiss. The Purchase Price shall be allocated among the Parcels and parcels
constituting the Leasehold Estate Land in a manner to be agreed upon by Prentiss
and Brandywine OP on or before the Closing Date.

         2.3 DEPOSIT. Within three (3) days after the execution hereof by both
Prentiss and Brandywine OP and as a condition precedent to the effectiveness of
this Agreement,

                                       8
<PAGE>

Brandywine OP shall deliver to Escrow Agent a wire transfer or check (a) in the
sum of Fifty Dollars ($50.00) (the "INDEPENDENT CONSIDERATION"), payable to the
order of Prentiss representing the Independent Consideration for Prentiss'
execution of this Agreement and agreement to provide Brandywine OP with the
Study Period (which check or the proceeds of which wire transfer shall
thereafter be delivered by Escrow Agent to Prentiss), and (b) in the sum of
$200,000.00 (the proceeds of which wire transfer or check Escrow Agent shall
deposit and invest in an interest bearing account at a financial institution
acceptable to Brandywine OP or as otherwise agreed to in writing by Prentiss and
Brandywine OP). The proceeds of the wire transfer or check are referred to
herein as the "DEPOSIT" and Escrow Agent shall hold and invest the Deposit
pursuant to the terms, conditions and provisions of this Agreement. All accrued
interest on the Deposit shall become part of the Deposit. The Deposit
(regardless of whether it is the proceeds of a wire transfer or check) shall be
either (a) returned to Brandywine OP pursuant hereto, or (b) paid to Prentiss
pursuant hereto. For purposes of reporting earned interest with respect to the
Deposit, Prentiss' Federal Tax Identification Number is 75-2672997, and
Brandywine OP's Federal Tax Identification Number is 23-2862640.

         2.4 STUDY PERIOD.

             (a) Brandywine OP and its agents, contractors and duly authorized
representatives shall have the right, until 5:00 p.m., Dallas, Texas time on the
last day of the Study Period, and thereafter unless, as provided below,
Brandywine OP notifies Prentiss in writing prior to the expiration of the Study
Period that Brandywine OP has elected to terminate this Agreement, to enter upon
the Real Property and to perform, at Brandywine OP's expense, such economic,
surveying, engineering, topographic, environmental, marketing and other tests,
studies and investigations as Brandywine OP may deem appropriate. If such tests,
studies and investigations do not warrant, in Brandywine OP's sole, absolute and
unreviewable discretion, the purchase of the Property for the purposes
contemplated by Brandywine OP, then Brandywine OP may elect not to proceed with
this transaction and shall notify Prentiss and Escrow Agent, in writing prior to
the expiration of the Study Period, that Brandywine OP has elected to terminate
this Agreement, in which event this Agreement automatically shall terminate, the
Deposit shall be promptly returned to Brandywine OP and Brandywine OP and
Prentiss shall be released from all further liability or obligation hereunder
except those which expressly survive a termination of this Agreement. If
Brandywine OP does not so notify Prentiss of its determination to terminate this
Agreement prior to the expiration of the Study Period, then Brandywine OP shall
be deemed to have waived its right to terminate this Agreement pursuant to this
SECTION 2.4.

             (b) Prentiss has delivered or made available at the Property the
following to Brandywine OP:

                 (1) Copies of all Leases in effect as of the date of this
         Agreement, together with, to the extent in Prentiss' possession or
         reasonably available to Prentiss, copies of all correspondence received
         from or sent to tenants of the Property.

                 (2) a Rent Roll (herein so called) certificate (with current
         rent roll and accounts receivable report attached) for the Property
         containing the following information with respect to each Lease: (i) a
         description of the space occupied thereby

                                       9
<PAGE>

         (including square feet, type of space, floor and tenant's pro rata
         share of common elements), (ii) tenant's name, (iii) the commencement
         date and expiration date thereof, (iv) the rental rate per square foot,
         (v) the amount of fixed monthly rental, (vi) the amount of any
         percentage or other additional rental and/or common area maintenance,
         tax, insurance and operating expenses and any other charges payable
         thereunder and, if applicable, the base year used in each Lease, (vii)
         the amount of any prepayment in rental, (viii) the amount of the
         security deposit or any other deposit thereunder, (ix) any free rent,
         concessions, rebates, refunds, refurbishment allowances or other
         inducements which any tenant will be entitled to receive after December
         31, 2000 (including, without limitation, any of the foregoing that may
         be payable in connection with renewals, extensions or expansions
         expressly contemplated in any of such Leases), (x) any options provided
         thereunder, including, without limitation, any renewal options,
         expansion options, purchase options and rights of first refusal and
         (xi) delinquency in rental or other charges set forth in the attached
         accounts receivable report.

                 (3) To the extent in Prentiss' possession or reasonably
         available to Prentiss, copies of all Authorizations including, without
         limitation, all certificates of occupancy, permits, authorizations,
         approvals (including drawings and enacting ordinances, if any), special
         exceptions, variances, and licenses issued by Governmental Authorities
         having jurisdiction over the Property and copies of all certificates
         issued by the local board of fire underwriters (or other body
         exercising similar functions) relating to the Property. For the purpose
         of this Agreement any Submission Matters in the possession of Prentiss
         or Prentiss' management company shall be deemed to be "reasonably
         available to Prentiss."

                 (4) To the extent in Prentiss' possession or reasonably
         available to Prentiss: (X) operating statements showing all income and
         expenses, profits and losses of the Property for the previous three (3)
         calendar years, which shall reflect (i) ad valorem taxes for the City,
         County and State or Commonwealth; (ii) expenses incurred for such
         period for water, electricity, natural gas and other utility charges;
         (iii) other operating expenses; (iv) total rents collected from tenants
         for such periods; and (v) other revenue collected and nature of such
         revenue; and (Y) financial statements for the Property for the previous
         three (3) calendar years, including, if available, the reports of
         accountants thereon.

                 (5) Operating and capital expenditure budgets for the current
         calendar year and, to the extent in Prentiss' possession or reasonably
         available to Prentiss, for the previous three (3) calendar years.

                 (6) All existing surveys and title policies for the Property
         that are reasonably available to Prentiss.

                 (7) A complete list of all Operating Agreements and leasing
         commission agreements in effect as of the date of this Agreement and
         complete copies of all such Operating Agreements and leasing commission
         agreements.

                 (8) A complete list of all Tangible Personal Property.

                                       10
<PAGE>

                 (9) To the extent in Prentiss' possession or reasonably
         available to Prentiss, any information in Prentiss' possession or
         reasonably available to Prentiss regarding current renditions or
         assessments on the Property or notices relative to change in valuation
         for ad valorem taxes.

                 (10) A complete list of all Warranties and Guaranties in effect
         as of the date of this Agreement and complete copies of all such
         Warranties and Guaranties.

                 (11) Copies of all soil tests, structural engineering tests,
         inspection reports, asbestos surveys, masonry tests, percolation tests,
         water, oil, gas, mineral, radon, formaldehyde, PCB or other
         environmental tests, audits or reports, market studies and site plans
         related to the Property in Prentiss' possession or reasonably available
         to Prentiss, together with copies of any and all correspondence,
         reports and other written documentation regarding the environmental
         aspects of the property or any toxic substances or equipment affecting
         or related to the Property.

                 (12) If in Prentiss' possession or reasonably available to
         Prentiss, copies of complete sets of all architectural, mechanical,
         structural and/or electrical plans and specifications used in
         connection with the construction of or alterations or repairs to the
         Property.

                 (13) If in Prentiss' possession or reasonably available to
         Prentiss, copies of as-built plans and specifications for the Property.

                 (14) Parking, structural, mechanical or other engineering
         reports or studies related to the Property, if any, in Prentiss'
         possession or reasonably available to Prentiss.

                 (15) To the extent in the possession of Prentiss or any
         affiliate of Prentiss or Prentiss' property manager, copies of credit
         reports and financial information on all tenants in possession of any
         of the Property and of any guarantors of such tenants' obligations.

                 (16) Copies of all approvals from any owners associations
         having jurisdiction over the Real Property and copies of all
         correspondence from any such owners association.

                 (17) Copies of the Existing Notes, Existing Liens and copies of
         any uncured notices of default or event of default from the holder(s)
         of the Existing Notes.

                 (18) A copy of each Ground Lease, and all amendments thereto.

                 (19) Copies of all Insurance Policies in effect, together with
         the name and telephone number of either a contact person at each
         insurance company or the insurance broker involved with the issuance of
         the Insurance Policies.

         During the Study Period and thereafter until the Closing, Prentiss
shall make available to Brandywine OP, copies of all materials, correspondence,
books, records, financial statements,

                                       11
<PAGE>

operating statements and any and all other materials or information relating to
the Property which come into Prentiss' possession or control or are otherwise
reasonably available to Prentiss from and after the date on which the Submission
Matters were delivered to Brandywine OP.

         Notwithstanding anything herein to the contrary, although Brandywine OP
has not received all of the deliveries described in this SECTION 2.4(b),
Brandywine OP has completed its feasibility study pursuant to SECTION 2.4(a) but
reserves the right to require, and Prentiss hereby agrees to deliver, to the
extent available to it, any item described in SECTION 2.4(b) not previously
delivered at any time during the period expiring six (6) months after the
Closing Date, which agreement shall survive the Closing Date for such six (6)
month period.

             (c) Brandywine OP shall indemnify and defend Prentiss against any
loss, damage or claim for personal injury or property damage (including
reasonable attorney's fees) arising from the entry upon the Property pursuant to
this SECTION 2.4 by Brandywine OP or any agents, contractors or employees of
Brandywine OP. Brandywine OP, at its own expense, shall restore any damage to
the Property caused by any of the tests or studies made by Brandywine OP. This
provision shall survive any termination of this Agreement and a closing of the
transaction contemplated hereby.

             (d) On or before 5:00 p.m. Dallas, Texas time on the date that is
five (5) days after the date of this Agreement, Prentiss shall deliver to
Brandywine OP, at Prentiss' sole cost and expense, the most recent Surveys of
the Land and the Improvements for all of the Land and Improvements which
constitute the Property, which are in the possession of Prentiss. Such Surveys
shall have been prepared by a Surveyor(s) licensed to practice in the State
where the Property is located. During the Study Period, Brandywine OP shall have
the right to update such Surveys, at Brandywine OP's sole cost. On or before the
Closing Date, Brandywine OP shall cause the Title Company to furnish to
Brandywine OP, at Prentiss' sole cost and expense, (i) a title insurance
commitment bearing an effective date subsequent to the date of this Agreement
issued by the Title Company covering the Real Property, binding the Title
Company to issue a ALTA Form Owner's Policy of Title Insurance, showing title
(which shall be leasehold title in the case of the Leasehold Estate Land) to be
held currently by Prentiss in a good, indefeasible and insurable condition,
together with legible copies of all documents identified in such title insurance
commitment as exceptions to title certified as true and complete by the Title
Company (collectively, the "TITLE COMMITMENT"), and (ii) reports of searches of
the Uniform Commercial Code records of both the county and State in which the
Property is located (collectively, the "UCC REPORTS") with respect to the state
of title to the Property. Prior to the expiration of the Study Period,
Brandywine OP shall notify Prentiss of any matters shown on the Survey or
identified in the Title Commitment or the UCC Reports that Brandywine OP is
unwilling to accept (collectively, "BRANDYWINE OP'S OBJECTIONS"); however,
Brandywine OP may not object to any Ground Lease, the Existing Notes and
Existing Liens. If any of Brandywine OP's Objections consist of delinquent
taxes, mortgages, deeds of trust, security agreements, construction or
mechanics' liens, tax liens or other liens or charges in a fixed sum or capable
of computation as a fixed sum, then, to that extent, notwithstanding anything
herein to the contrary, Prentiss shall be obligated to pay and discharge (or
bond against in a manner sufficient to cause the Title Company to insure over
such Brandywine OP's Objections) any such Brandywine OP's Objections and Escrow
Agent is authorized to pay and discharge at Closing such Brandywine OP's
Objections to the extent not paid and discharged or bonded against at Closing.

                                       12
<PAGE>

Prentiss shall not be obligated to incur any expenses to cure any non-monetary
Brandywine OP's Objections (including, without limitation, any lis pendens filed
against the Property) unless Prentiss agrees to cure such non-monetary
Brandywine OP's Objections as hereinafter provided. Prentiss shall notify
Brandywine OP on or before the Closing Date whether Prentiss agrees to cure such
non-monetary Brandywine OP's Objections. If Prentiss notifies Brandywine OP in
writing on or before the Closing Date that Prentiss agrees to cure such
non-monetary Brandywine OP's Objections, Prentiss shall correct such
non-monetary Brandywine OP's Objections on or before the Closing Date to the
reasonable satisfaction of Brandywine OP. If Prentiss does not notify Brandywine
OP on or before the Closing Date of its agreement to cure such non-monetary
Brandywine OP's Objections, Prentiss shall be deemed to have elected not to cure
such non-monetary Brandywine OP's Objections, and Brandywine OP shall elect (1)
to waive such non-monetary Brandywine OP's Objections or (2) to terminate this
Agreement, in which case the Deposit shall be promptly returned to Brandywine OP
and the parties hereto shall be released from all further obligations hereunder
except those which expressly survive a termination of this Agreement. Prentiss
shall not, after the date of this Agreement, subject the Real Property to or
permit or suffer to exist any liens, encumbrances, covenants, conditions,
restrictions, easements or other title matters or seek any zoning changes or
take any other action which may affect or modify the status of title without
Brandywine OP's prior written consent. The Existing Notes, Existing Liens, each
Ground Lease and all title matters revealed by the Title Commitment, UCC Reports
and Survey and not objected to by Brandywine OP as provided above (other than
those rendering title defeasible and delinquent taxes, mortgages, deeds of
trust, security agreements and other liens and charges that are to be paid at
Closing or bonded against as provided above) shall be deemed Permitted Title
Exceptions. Notwithstanding the foregoing, Brandywine OP shall not be required
to take title to the Real Property subject to any matters which (i) may arise
subsequent to the effective date of the Title Commitment, UCC Reports and Survey
examined by Brandywine OP during the Study Period and (ii) impairs title to any
portion of the Property and will not be released or bonded against on or before
the Closing Date. If a title exception is disclosed by the Title Company which
was not shown in the Title Commitment or Survey and was not the result of
Prentiss' acts or omissions, then, unless Prentiss notifies Brandywine OP in
writing by the Closing Date that Prentiss agrees to take such action as may be
necessary to release such title exception on or before the Closing Date,
Brandywine OP may (i) terminate this Agreement by written notice to Prentiss, in
which event the Deposit shall be promptly returned to Brandywine OP and the
parties hereto shall be released from all further obligations hereunder except
those which expressly survive a termination of this Agreement, or (ii) waive its
objections to such title exception and consummate the transactions contemplated
herein.

             (e) Notwithstanding anything in this Agreement to the contrary, the
parties hereto agree that Grande B shall be acquiring Lake Center IV on the
Closing Date, and the Deed, Bill of Sale, Assignment of Leases and other
conveyance documents to be executed and delivered by Prentiss as to Lake Center
IV on the Closing Date shall name Grande B as the purchaser of Lake Center IV.

                                       13
<PAGE>

                                  ARTICLE III.
                    PRENTISS' REPRESENTATIONS AND WARRANTIES

         To induce Brandywine OP to enter into this Agreement and to acquire the
Property, Prentiss makes the following representations and warranties with
respect to the Property, upon each of which Prentiss acknowledges and agrees
that Brandywine OP is entitled to rely and has relied:

         3.1 ORGANIZATION AND POWER. Prentiss is a limited partnership duly
formed, validly existing and in good standing under the laws of the State of
Delaware, is duly qualified to transact business in the Commonwealth of
Pennsylvania and State of Delaware, and has all requisite powers and all
material governmental licenses, authorizations, consents and approvals to carry
on its business as now conducted and to enter into and perform its obligations
hereunder and under any document or instrument required to be executed and
delivered on behalf of Prentiss hereunder.

         3.2 AUTHORIZATION, EXECUTION AND DISCLOSURE. This Agreement has been
duly authorized by all necessary action on the part of Prentiss, has been duly
executed and delivered by Prentiss, constitutes the valid and binding agreement
of Prentiss and is enforceable in accordance with its terms, subject to the
effect of applicable bankruptcy, insolvency, reorganization, arrangement,
moratorium or other similar laws affecting the rights of creditors generally.
Except for the consents of (i) partners in Lot 21 Associates, L.P. and Project
127 Partners, L.P. that are not affiliates of Prentiss, and (ii) the holders of
the Existing Notes, there is no other person or entity who has an ownership
interest in the Property or whose consent is required in connection with
Prentiss' performance of its obligations hereunder which has not been obtained.
The person executing this Agreement on behalf of Prentiss has the authority to
do so. Prentiss has not and will not intentionally conceal any information
regarding the Property.

         3.3 NON-CONTRAVENTION. The execution and delivery of, and the
performance by Prentiss of its obligations under, this Agreement do not and will
not (a) contravene, or constitute a default under, any provision of (i)
Prentiss' Organizational Documents, (ii) applicable law or regulation or any
agreement, judgment, injunction, order, decree or other instrument binding upon
Prentiss or to which the Property is subject, the result of which could have a
material adverse effect on the value of the Property or Prentiss' ability to
convey the Property to Brandywine OP and/or Prentiss' ability to perform its
obligations under this Agreement, or (iii) result in the creation of any lien or
other encumbrance on any asset of Prentiss. There are no outstanding agreements
(written or oral) pursuant to which Prentiss (or any predecessor to or
representative of Prentiss) has agreed to sell or has granted an option or right
of first refusal to purchase the Property or any part thereof.

         3.4 NO SPECIAL TAXES. Prentiss has no knowledge of, nor has it received
any notice of, any special taxes or assessments relating to the Property or any
part thereof or any planned public improvements that may result in a special tax
or assessment against the Property.

         3.5 COMPLIANCE WITH EXISTING LAWS AND RESTRICTIVE COVENANTS. To
Prentiss' knowledge, Prentiss possesses all Authorizations, each of which is
valid and in full force and effect, and no provision, condition or limitation of
any of the Authorizations has been breached

                                       14
<PAGE>

or violated. Prentiss has received no notice within the past three years, of any
existing or threatened violation of any provision of any (a) Applicable Laws
including, but not limited to, those of environmental agencies or insurance
boards of underwriters with respect to the ownership, operation, use,
maintenance or condition of the Property or any part thereof, or requiring any
repairs or alterations to the Property other than those that have been made
prior to the date hereof, and (b) restrictive covenants or deed restrictions
affecting the Real Property.

         3.6 PERSONAL PROPERTY. Except for the Existing Liens, all of the
Personal Property being conveyed by Prentiss hereunder is free and clear of all
liens and encumbrances except for those which will be discharged by Prentiss at
Closing, and Prentiss has good and merchantable title thereto and the right to
convey same in accordance with the terms of this Agreement.

         3.7 OPERATING AGREEMENTS. There are no management, service, supply,
maintenance, employment or other contracts in effect with respect to the
Property of any nature whatsoever, written or oral, other than the Assumed
Operating Agreements and the other Operating Agreements to be terminated
pursuant to the last sentence of this SECTION 3.7. To Prentiss' knowledge,
Prentiss has performed all of its obligations under each of the Assumed
Operating Agreements in all material respects and no fact or circumstance has
occurred which, by itself or with the passage of time or the giving of notice or
both, would constitute a default under any of the Assumed Operating Agreements.
To Prentiss' knowledge, all other parties to the Assumed Operating Agreements
have performed all of their obligations thereunder in all material respects, and
are not in default thereunder in any material respect. Prentiss has received no
notice of any intention by any of the parties to any of the Assumed Operating
Agreements to cancel the same, nor has Prentiss canceled any of same. At the
written request of Brandywine OP, Prentiss shall cause any Operating Agreements
designated by Brandywine OP which are terminable without penalty to be
terminated as of the Closing Date.

         3.8 CONDEMNATION PROCEEDINGS; ROADWAYS. Prentiss has received no notice
of any condemnation or eminent domain proceeding pending or, to Prentiss'
knowledge, no such action is threatened, against the Property or any part
thereof. Prentiss has no knowledge of any change or proposed change in the
route, grade or width of, or otherwise affecting, any street, creek or road
adjacent to or serving the Real Property.

         3.9 ACTIONS OR PROCEEDINGS. There is no action, suit or proceeding
pending or known to Prentiss to be threatened against or affecting Prentiss in
any court, before any arbitrator or before or by any Governmental Authority
which (a) in any manner raises any question affecting the validity or
enforceability of this Agreement or any other agreement or instrument to which
Prentiss is a party or by which it is bound and that is or is to be used in
connection with, or is contemplated by, this Agreement, (b) is reasonably likely
to materially and adversely affect the business, financial position or results
of operations of Prentiss or the Property, (c) is reasonably likely to
materially and adversely affect the ability of Prentiss to perform its
obligations hereunder, or under any document to be delivered pursuant hereto,
(d) is reasonably likely to create a lien on the Property, any part thereof or
any interest therein or (e) is reasonably likely to otherwise materially and
adversely affect the Property, any part thereof or any interest therein or the
use, operation, condition or occupancy thereof.

         3.10 BANKRUPTCY. No Act of Bankruptcy has occurred with respect to
Prentiss.

                                       15
<PAGE>

         3.11 HAZARDOUS SUBSTANCES. To Prentiss' knowledge, neither Prentiss nor
any previous owner, tenant, occupant or user of the Property, nor any other
person, has engaged in or permitted any operations or activities upon, or any
use or occupancy of the Property or any portion thereof, for the purpose of or
in any way involving the handling, manufacture, treatment, storage, use,
generation, release, discharge, refining, dumping or disposal of any Hazardous
Materials on, under, in or about the Property in violation of any Applicable
Laws. To Prentiss' knowledge, no Hazardous Materials have migrated from or to
the Property upon, about, or beneath other properties in violation of any
Environmental Requirements. To Prentiss' knowledge, neither the Property nor its
existing or prior uses fail or failed to materially comply with Environmental
Requirements. Prentiss has no knowledge of any permits, licenses or other
authorizations which are required under any Environmental Requirements with
regard to the current uses of the Property which have not been obtained and
complied with. To Prentiss' knowledge, neither Prentiss nor any prior owner,
occupant or user of the Property has received any written notice concerning any
alleged violation of Environmental Requirements in connection with the Property
or any liability for Environmental Damages in connection with the Property for
which Prentiss (or Brandywine OP after Closing) may be liable. To Prentiss'
knowledge, no Hazardous Materials are constructed, deposited, stored or
otherwise located on, under, in or about the Property in violation of any
Environmental Requirements. To Prentiss' knowledge, there exists no writ,
injunction, decree, order or judgment outstanding, nor any lawsuit, claim,
proceeding, citation, summons or investigation, pending or threatened, relating
to any alleged violation of Environmental Requirements on the Property, or from
the suspected presence of Hazardous Materials thereon, or relating to any
Environmental Damages. To Prentiss' knowledge, there are no underground or above
ground chemical treatment or storage tanks, or gas or oil wells are located on
the Property. The representations and warranties made by Prentiss in this
SECTION 3.11 shall be subject to the matters disclosed in the environmental
reports delivered by Prentiss to Brandywine OP pursuant to SECTION 2.4(b)(12)
hereof.

         3.12 PARTIES IN POSSESSION. There are no parties in possession of the
Property except for tenants under written leases, copies of which will be
delivered to Brandywine OP pursuant to the terms hereof.

         3.13 LEASES. There are no leases, concessions or occupancy agreements
in effect with respect to the Real Property other than the Leases listed on the
Rent Roll attached as SCHEDULE 3.13; and SCHEDULE 3.13 attached hereto is a
complete and correct list of all Leases in effect on the date of this Agreement.
Prentiss has not sent out any written notice of any default to any tenant under
any Lease which has not been cured except as set forth on SCHEDULE 3.13. To
Prentiss' knowledge, Prentiss has performed all obligations required of it under
all of the Leases and there remain no unfulfilled obligations of Prentiss under
the Leases, the nonperformance of which could entitle a tenant to damages under
such Lease or could cause Prentiss to be in default under such Lease. Except as
shown on SCHEDULE 3.13, no tenant has given written notice to Prentiss of its
intention to institute litigation with respect to any Lease that has not been
dismissed, and Prentiss has not been served with a citation notifying Prentiss
of any litigation with respect to any Lease that has not been dismissed. None of
the Leases and none of the rents or other amounts payable thereunder have been
assigned, pledged or encumbered except for (a) any assignments, pledges or
encumbrances which will be fully released on or before the Closing Date, and (b)
the Existing Liens. The Rent Roll is true, correct and complete in all material
respects as of the date shown in the Rent Roll and, to Prentiss' knowledge,
there has

                                       16
<PAGE>

been no material adverse change with respect to any of the items shown on the
Rent Roll during the period from the date thereof to the date of this Agreement,
except as shown thereon.

         3.14 LEASED PROPERTY. To Prentiss' knowledge, all leases of the Leased
Property, if any, are in good standing and free from default.

         3.15 NO UNPAID CHARGES. Subject to SECTION 7.8 hereof, there are no
unpaid charges, debts, liabilities, claims or obligations arising from the
construction, occupancy, ownership, use or operation of the Property which could
give rise to any mechanic's or materialmen's or other statutory lien against the
Property, or any part thereof, or for which Brandywine OP will be responsible or
which will be due upon the initial occupancy of vacant space (such as a water or
sewer connection or tap-in fee).

         3.16 CONDITION OF IMPROVEMENTS. Prentiss has not received any written
notice, from any third party alleging that (a) any of the Improvements (i) are
defective in design or construction, (ii) are not in operating condition and a
satisfactory state of repair, or (iii) have roof leaks, (b) any mechanical
systems are not in reasonable working order and repair, or (c) Prentiss has
failed to operate the Property in a commercially reasonable manner consistent
with a modern office building; provided, however, the foregoing representation
and warranty as to notices received shall not include any representation or
warranty as to notices concerning the aesthetic or other subjective quality of
the design of the Property or any system, element or component thereof and no
representation or warranty shall be deemed made as to any defect disclosed in
any property condition report obtained by Brandywine OP in connection with the
Property.

         3.17 ACCESS. Prentiss has no knowledge of any pending or threatened
governmental proceeding or any other fact or condition which would limit or
result in the termination of the Property's existing access to and from public
streets or roads.

         3.18 NO COMMITMENTS. No commitments have been made to any Governmental
Authority, utility company, school board, church or other religious body, or any
homeowners' association or any other organization, group or individual, relating
to the Property which would impose an obligation upon Brandywine OP to make any
contribution or dedication of money or land or to construct, install or maintain
any improvements of a public or private nature on or off the Property. Without
limiting the generality of the foregoing, Prentiss is not a party to any paving
agreements or undertakings, payback agreements, revenue bonds, utility debt
service expenses or other charges or expenses upon or relating to any of the
Property or applicable thereto.

         3.19 PRENTISS IS NOT A "FOREIGN PERSON". Prentiss is not a "FOREIGN
PERSON" within the meaning of Section 1445 of the Internal Revenue Code, as
amended (i.e., Prentiss is not a foreign corporation, foreign partnership,
foreign trust, foreign estate or foreign person as those terms are defined in
the Internal Revenue Code and regulations promulgated thereunder).

         3.20 LEASING COMMISSIONS. No brokerage or leasing commissions or other
fees or compensation are due or payable, or which will become due and payable as
a result of agreements in place, to any person, firm, corporation or other
entity with respect to or on account

                                       17
<PAGE>

of any of the Leases or any extension or renewals thereof, except as set forth
on SCHEDULE 3.20 OR 6.4(g) hereof.

         3.21 OTHER AGREEMENTS. There are no options, contracts or other
obligations outstanding for the sale, exchange or transfer of any of the
Property or any interest therein which would be superior to the rights of
Brandywine OP under this Agreement or which would survive Closing.

         3.22 EXISTING SECURED INDEBTEDNESS. There is no debt secured by liens
on the Real Property, or any portion thereof, which will not be released and
discharged as of the Closing, other than the Existing Notes and the Existing
Liens. Prentiss is not in default under the Existing Notes or the Existing
Liens, to Prentiss' knowledge, no event has occurred which, with the passage of
time or the giving of notice, or both, would constitute a default thereunder,
and EXHIBIT E is true, accurate and complete in all material respects.

         3.23 EMPLOYMENT ON "AT-WILL" BASIS. All persons and entities presently
employed in connection with the operation and maintenance of the Property are
employed on an "AT WILL" basis, are dischargeable upon thirty (30) days' notice
and, unless otherwise directed by Brandywine OP, shall be terminated by Prentiss
as of Closing. There are no labor disputes pending, nor to the best of Prentiss'
knowledge, contemplated pertaining to the operation or maintenance of the
Property, or any part thereof. Prentiss has no employment agreements, either
written or oral, with any person which would require Brandywine OP to employ any
person after the date hereof or the Closing Date.

         3.24 GROUND LEASE. Each Ground Lease is valid and in full force and
effect. Prentiss is not in default under any Ground Lease; to Prentiss'
knowledge, no event has occurred which, with the passage of time or the giving
of notice, or both, would constitute a default under any Ground Lease; and
EXHIBIT B is a true, accurate and complete listing, in all material respects, of
each Ground Lease and all amendments thereto.

         3.25 LIMITATIONS ON REPRESENTATIONS AND WARRANTIES. BRANDYWINE OP
HEREBY AGREES AND ACKNOWLEDGES THAT, EXCEPT AS SET FORTH IN THIS ARTICLE III, OR
AS OTHERWISE EXPRESSLY STATED HEREIN OR IN THE DEED OR IN ANY DOCUMENTS EXECUTED
IN CONNECTION HEREWITH, NEITHER PRENTISS NOR ANY AGENT, ATTORNEY, EMPLOYEE OR
REPRESENTATIVE OF PRENTISS HAS MADE ANY REPRESENTATION WHATSOEVER REGARDING THE
SUBJECT MATTER OF THIS AGREEMENT, OR ANY PART HEREOF, INCLUDING (WITHOUT
LIMITING THE GENERALITY OF THE FOREGOING) REPRESENTATIONS OR WARRANTIES AS TO
THE PHYSICAL NATURE OR CONDITION OF THE PROPERTY OR THE CAPABILITIES THEREOF,
AND THAT BRANDYWINE OP, IN EXECUTING, DELIVERING AND/OR PERFORMING THIS
AGREEMENT, DOES NOT RELY UPON ANY STATEMENT AND/OR INFORMATION TO WHOMEVER MADE
OR GIVEN, DIRECTLY OR INDIRECTLY, ORALLY OR IN WRITING, BY ANY INDIVIDUAL, FIRM
OR CORPORATION EXCEPT THOSE EXPRESSLY CONTAINED HEREIN OR DELIVERED PURSUANT
THERETO OR IN ANY DOCUMENTS EXECUTED IN CONNECTION HEREWITH. EXCEPT AS OTHERWISE
PROVIDED HEREIN, BRANDYWINE OP AGREES TO TAKE THE PROPERTY "AS IS,"

                                       18
<PAGE>

AS OF THE DATE HEREOF, REASONABLE WEAR AND TEAR EXCEPTED. IN ADDITION, EXCEPT AS
SET FORTH HEREIN, PRENTISS MAKES NO REPRESENTATIONS OR WARRANTIES REGARDING THE
COMPLIANCE WITH ANY ENVIRONMENTAL REQUIREMENTS, INCLUDING THE EXISTENCE IN OR ON
THE PROPERTY OF HAZARDOUS MATERIALS. THE PROVISIONS OF THIS PARAGRAPH SHALL
SURVIVE THE CLOSING OR ANY TERMINATION HEREOF.

Each of the representations and warranties contained in this ARTICLE III and its
various subparagraphs are intended for the benefit of Brandywine OP and may be
waived in whole or in part by Brandywine OP. All rights and remedies arising in
connection with the untruth or inaccuracy of any such representations and
warranties shall survive the Closing of the transaction contemplated hereby as
provided in SECTION 10.11 hereof, except to the extent that Prentiss gives
Brandywine OP written notice prior to Closing of the untruth or inaccuracy of
any representation or warranty, Brandywine OP otherwise obtains actual knowledge
prior to Closing of the untruth or inaccuracy of any representation or warranty,
and Brandywine OP nevertheless elects to close this transaction. Brandywine OP
shall be deemed to have actual knowledge of the untruth or inaccuracy of any
representation or warranty only if (i) Brandywine OP receives written notice
from Prentiss satisfying the foregoing requirements, or (ii) Gerard H. Sweeney,
George Hasenecz, Michael Diliberto, Suzanne Stumpf or Brad A. Molotsky has
actual knowledge of any such untruth or inaccuracy. Except to the extent
otherwise expressly provided in the immediately preceding sentence, no
investigation, audit, inspection, review or the like conducted by or on behalf
of Brandywine OP shall be deemed to terminate the effect of any such
representations, warranties and covenants, it being understood that Brandywine
OP has the right to rely thereon and that each such representation and warranty
constitutes a material inducement to Brandywine OP to execute this Agreement and
to close the transaction contemplated hereby and to pay the Purchase Price to
Prentiss.

If any of Prentiss' representations and warranties made hereunder are found by
Brandywine OP to be incorrect prior to Closing to the extent they affect the
Property or its operation in any material respect, Brandywine OP shall inform
Prentiss in writing and Brandywine OP's sole remedy, except as otherwise
expressly provided in CLAUSE (a)(ii) of the first sentence of SECTION 9.3 hereof
or the last sentence of SECTION 9.3 hereof, shall be termination of this
Agreement on account thereof and refund of the Deposit. If Brandywine OP elects
not to so terminate this Agreement, any remedy of Brandywine OP for breach of
such warranties and representations made prior to the Closing shall be deemed to
be irrevocably waived. Notwithstanding anything to the contrary contained in
this Article, if Prentiss breaches any representation or warranty made by
Prentiss and if prior to Closing Brandywine OP notifies Prentiss that it elects
to terminate this Agreement on account of such breach, Prentiss may by written
notice to Brandywine OP given or before the Closing Date agree to cure the
breach (which breach must be cured on or before the Closing Date), and
Brandywine OP shall thereupon be obligated to close the transaction and accept
such cure as Brandywine OP's sole remedy for such breach.

The term "TO PRENTISS' KNOWLEDGE" or similar phrase shall mean the knowledge of
Prentiss' chief executive officer, general counsel, chief financial officer,
Hank Gulbrandsen, Peter Hausmann and the current building engineer, property
manager and leasing agent (collectively, "PRENTISS' PERSONNEL WITH KNOWLEDGE")
for the Property and such inquiry shall include the direction by

                                       19
<PAGE>

Prentiss to such persons to review all files in their possession relating to the
operation, ownership, maintenance and management of the Property. Prentiss
covenants that if prior to Closing Prentiss obtains actual knowledge that any of
the facts represented and warranted by Prentiss under this Agreement are or
become untrue or inaccurate in any material respect, it will promptly inform
Brandywine OP in writing of its discovery.

Prentiss' Personnel with Knowledge shall not have any personal liability under
this Agreement in their respective capacities as officers and/or directors of
Prentiss.

                                  ARTICLE IV.
                 BRANDYWINE OP'S REPRESENTATIONS AND WARRANTIES

         To induce Prentiss to enter into this Agreement and to convey the
Property, Brandywine OP hereby makes the following representations and
warranties, upon each of which Brandywine OP acknowledges and agrees that
Prentiss is entitled to rely and has relied:

         4.1 ORGANIZATION AND POWER. Brandywine OP is a limited partnership,
duly formed, validly existing and in good standing under the laws of the State
of Delaware, and has all requisite partnership powers and all material
governmental licenses, authorizations, consents and approvals required to carry
on its businesses as now conducted and to enter into and perform its obligations
under this Agreement and any document or instrument required to be executed and
delivered on behalf of Brandywine OP hereunder. Brandywine OP has the financial
capability to acquire the Property pursuant to this Agreement.

         4.2 NON-CONTRAVENTION. The execution and delivery of this Agreement and
the performance by Brandywine OP of its obligations hereunder do not and will
not contravene, or constitute a default under, any provisions of Brandywine OP's
Organizational Documents or applicable law or regulation, or any agreement,
judgment, injunction, order, decree or other instrument binding upon Brandywine
OP.

         4.3 LITIGATION. There is no action, suit or proceeding, pending or
known to be threatened, against or affecting Brandywine OP or Brandywine OP in
any court or before any arbitrator or before any Governmental Authority which
(a) in any manner raises any question affecting the validity or enforceability
of this Agreement or any other agreement or instrument to which Brandywine OP is
a party or by which it is bound and that is to be used in connection with, or is
contemplated by, this Agreement, (b) could materially and adversely affect the
business, financial position or results of operations of Brandywine OP, or (c)
could materially and adversely affect the ability of Brandywine OP to perform
its obligations hereunder, or under any document to be delivered pursuant
hereto.

         4.4 BANKRUPTCY. No Act of Bankruptcy has occurred with respect to
Brandywine OP.

         4.5 AUTHORIZATION, EXECUTION AND DISCLOSURE. This Agreement has been
duly authorized by all necessary action on the part of Brandywine OP, has been
duly executed and delivered by Brandywine OP, constitutes the valid and binding
agreement of Brandywine OP and is enforceable in accordance with its terms,
subject to the effect of applicable bankruptcy, insolvency, reorganization,
arrangement, moratorium or other similar laws affecting the rights of creditors
generally.

                                       20
<PAGE>

                                   ARTICLE V.
                              CONDITIONS PRECEDENT

         5.1 AS TO BRANDYWINE OP'S OBLIGATIONS. Brandywine OP's obligations
hereunder are subject to the satisfaction of the following conditions precedent:

             (a) PRENTISS' DELIVERIES. Prentiss shall have delivered to or for
the benefit of Brandywine OP, on or before the Closing Date, all of the
documents and other information required of Prentiss pursuant to SECTIONS 7.2
AND 7.4 hereof.

             (b) REPRESENTATIONS, WARRANTIES AND COVENANTS; OBLIGATIONS OF
PRENTISS; CERTIFICATE. All of Prentiss' representations and warranties made in
this Agreement shall be true and correct in all material respects as of the date
hereof and as of the date of Closing as if then made; Prentiss shall have
performed in all material respects all of its covenants and other obligations
under this Agreement; and Prentiss shall have executed and delivered to
Brandywine OP at Closing a certificate to the foregoing effect.

             (c) TITLE INSURANCE. Good and indefeasible fee simple title to the
Fee Estate Land and good and indefeasible title to the Leasehold Estate Land
shall be insurable as such by the Title Company, subject only to Permitted Title
Exceptions as determined in accordance with SECTION 2.4 hereof and including,
without limitation, all applicable deletions of standard exceptions and
endorsements permitted under applicable state law which are customarily required
by institutional investors purchasing property comparable to the Property.

             (d) CONDITION OF IMPROVEMENTS. The Improvements and the Tangible
Personal Property (including but not limited to the mechanical systems,
plumbing, electrical, wiring, fixtures, heating, air conditioning and
ventilating equipment, elevators, boilers, equipment, roofs, structural members
and furnaces) shall be in the same condition at Closing as they are as of the
date hereof, reasonable wear and tear excepted. Prentiss shall not have removed
or caused or permitted to be removed any part or portion of the Real Property or
the Tangible Personal Property without Brandywine OP's prior written consent
unless the same is replaced, prior to Closing, with a similar item of at least
equal suitability, quality and value, free and clear of any lien or security
interest.

             (e) UTILITIES. All of the Utilities shall be installed in and
operating at the Property, and service shall be available for the removal of
garbage and other waste from the Property.

             (f) DUE DILIGENCE MATERIALS. All rent rolls, lists, schedules and
other documents furnished by Prentiss to Brandywine OP under this Agreement
shall be true and correct in all material respects, except for inaccuracies as
to which Brandywine OP was given written notice by Prentiss or otherwise had
actual knowledge prior to the end of the Study Period.

             (g) NO ADDITIONAL PROCEEDINGS; TENANT DEFAULTS. Except for matters
as to which Brandywine OP was given written notice by Prentiss or otherwise had
actual knowledge prior to the end of the Study Period, on the Closing Date,
there shall be no (a) litigation pending or threatened, seeking (i) to enjoin
the consummation of the transactions contemplated

                                       21
<PAGE>

hereunder, (ii) to recover title to the Property, or any part thereof or any
interest therein, (iii) to increase substantially ad valorem taxes theretofore
assessed against any of the Property, (iv) to enjoin the violation of any law,
rule, regulation, restrictive covenant or zoning ordinance that may be
applicable to the Property, or (v) claiming defaults or other liability of
Prentiss under Leases by tenants leasing five percent (5%) or more of the
rentable square feet of the Improvements, in the aggregate or (b) monetary
default in excess of thirty (30) days for which a written notice of default has
been given to a tenant and which constitutes an event of default under, and as
defined in, the applicable Lease, other material default or any threatened or
reasonably anticipated material default by tenants leasing five percent (5%) or
more of the rentable square feet of the Improvements, in the aggregate.

             (h) ESTOPPEL LETTERS. The estoppel letters to be delivered at
Closing pursuant to SECTION 7.2(g) hereof shall have been obtained and delivered
and shall reflect no facts at material variance with the facts disclosed on the
Rent Roll and records provided to Brandywine OP during the Study Period.

             (i) LENDER ESTOPPEL LETTERS. The lender estoppel letters to be
delivered at Closing pursuant to SECTION 7.2(y) hereof shall have been obtained
and delivered and shall reflect no facts at material variance with the facts
represented and warranted by Prentiss to Brandywine OP hereunder.

             (j) GROUND LESSOR ESTOPPEL LETTERS. Estoppel letters from each
Ground Lessor pursuant to SECTION 7.2(z) hereof.

             (k) ISRA. Prentiss shall obtain and deliver a Non-Applicability
Determination ("NON-APPLICABILITY DETERMINATION") from the Industrial Site
Evaluation Element of the New Jersey Department of Environmental Protection
pursuant to the Environmental Clean-Up Responsibility Act, as amended by the
Industrial Site Recovery Act, N.J.S.A. 13:1K-6 ET SEQ., the regulations
promulgated thereunder and any amending or successor legislation and regulations
in connection with the transfer of portions of the Property located in the State
of New Jersey by Prentiss to Brandywine OP.

             (l) OTHER ESTOPPEL LETTERS. Estoppel letters described in SECTION
7.2(w) hereof.

Each of the conditions contained in this SECTION 5.1 are intended for the
benefit of Brandywine OP and may be waived in whole or in part, by Brandywine
OP, but only by an instrument in writing signed by Brandywine OP.

         5.2 AS TO PRENTISS' OBLIGATIONS. Prentiss' obligations hereunder are
subject to the satisfaction of the following conditions precedent:

             (a) BRANDYWINE OP'S DELIVERIES. Brandywine OP shall have delivered
to or for the benefit of Prentiss, on or before the Closing Date, all of the
documents and payments required of Brandywine OP pursuant to SECTIONS 7.3 AND
7.4 hereof.

             (b) REPRESENTATIONS, WARRANTIES AND COVENANTS; OBLIGATIONS OF
BRANDYWINE OP. All of Brandywine OP's representations and warranties made in
this

                                       22
<PAGE>

Agreement shall be true and correct in all material respects as of the date
hereof and as of the date of Closing as if then made and Brandywine OP shall
have performed in all material respects all of its covenants and other
obligations under this Agreement.

         5.3 LOT 21 PROPERTY AND LOT 27 PROPERTY. Notwithstanding anything
herein to the contrary, in the event that the partners other than Prentiss (such
other partners being referred to herein as the "OTHER PARTNERS") in each of Lot
21 Associates, L.P., a Pennsylvania limited partnership (the "LOT 21 OWNER"),
and Project 127 Partners, L.P., a Pennsylvania limited partnership (the "LOT 27
OWNER"), do not consent to the sale of the Property owned by the Lot 21 Owner
(the "LOT 21 PROPERTY") and the sale of the Property owned by the Lot 27 Owner
(the "LOT 27 PROPERTY") by such time as the conditions precedent to the
obligations of Brandywine OP and Prentiss in ARTICLE V hereof have otherwise
been satisfied or waived, then Brandywine OP and Prentiss agree as follows:

             (a) The parties shall consummate the transactions on the terms set
forth herein, except that Prentiss shall not transfer fee title to either of the
Lot 21 Property or the Lot 27 Property at the Closing, and the total Purchase
Price in respect of the Lot 21 Property and the Lot 27 Property shall be reduced
by $7,800,000.00.

             (b) In addition to the foregoing, Prentiss and Brandywine OP shall
enter into an agreement on the Closing Date generally in the form of EXHIBIT G
hereto, which agreement shall be mutually agreed upon by Prentiss and Brandywine
OP within five (5) business days following the Effective Date.

Each of the conditions contained in this Section are intended for the benefit of
Prentiss and may be waived in whole or in part, by Prentiss, but only by an
instrument in writing signed by Prentiss.

                                  ARTICLE VI.
                              COVENANTS OF PRENTISS

         To induce Brandywine OP to enter into this Agreement and to purchase
the Property, and to pay the Purchase Price therefor, Prentiss covenants and
agrees to the following:

         6.1 OPERATING AGREEMENTS. Prior to the Closing Date, Prentiss shall not
enter into any new management agreement, maintenance or repair contract, supply
contract, lease in which it is lessee or other agreements with respect to the
Property which cannot be terminated on or before the Closing Date, nor shall
Prentiss enter into any agreements modifying the Operating Agreements in any
material respect, unless (a) any such agreement or modification will not bind
Brandywine OP or the Property after the date of Closing or (b) Prentiss has
obtained Brandywine OP's prior written consent to such agreement or
modification. Prentiss agrees to cancel and terminate effective as of the
Closing Date all property management agreements affecting the Property or any
portion thereof and the Operating Agreements to be terminated pursuant to the
last sentence of SECTION 3.7 hereof.

         6.2 WARRANTIES AND GUARANTIES. Prentiss shall not before or after
Closing release or modify any Warranties and Guaranties, if any, except with the
prior written consent of Brandywine OP.

                                       23
<PAGE>

         6.3 INSURANCE. Prior to the Closing Date, Prentiss shall pay all
premiums on, and shall not cancel or voluntarily allow to expire, any of
Prentiss' Insurance Policies unless such policy is replaced, without any lapse
of coverage, by another policy or policies providing coverage at least as
extensive as the policy or policies being replaced. Prentiss hereby indemnifies
and holds Brandywine OP harmless from and against all losses, costs, damages and
expenses resulting from actions involving bodily or personal injury or property
damage in or about any of the Property that occurred prior to the Closing Date,
regardless of when the claim was made, but only to the extent coverage under the
applicable Insurance Policy or Policies is not sufficient and paid, and this
indemnity shall survive the Closing Date.

         6.4 OPERATION OF PROPERTY PRIOR TO CLOSING. Prentiss and Brandywine OP
represent, warrant, covenant and agree with Brandywine OP that, between the date
of this Agreement and the date of Closing:

             (a) Subject to the restrictions contained herein, Prentiss shall
operate the Property in the same manner in which Prentiss operated the Property
prior to the execution of this Agreement, so as to keep the Property in good
condition, reasonable wear and tear excepted.

             (b) Prentiss shall maintain its books of account and records in the
usual, regular and ordinary manner, in accordance with sound accounting
principles applied on a basis consistent with the basis used in keeping its
books in prior years.

             (c) Prentiss shall maintain in full force and effect all Insurance
Policies.

             (d) Prentiss shall punctually perform and discharge all obligations
and undertakings of Prentiss under the Leases and shall not permit a default by
Prentiss to occur thereunder.

             (e) Prentiss shall use and operate the Property in compliance with
Applicable Laws and the requirements of any mortgage, ground lease, Lease,
Operating Agreement and Insurance Policy affecting the Property.

             (f) Prentiss shall cause to be paid prior to delinquency all ad
valorem and other taxes due and payable with respect to the Property or its
operation.

             (g) Without the express prior written consent of Brandywine OP
(which consent shall not be unreasonably withheld and shall be deemed to have
been given if Brandywine OP fails to respond to a written request from Prentiss
for such consent within two (2) business days following Brandywine OP's receipt
of any such request), Prentiss shall not: (i) enter into new Leases of any kind
or nature affecting the Property; or (ii) grant a renewal or extension of any
existing Lease, or consent to any assignment, sublease or expansion of any
existing lease or portion thereof which, by the terms of any such Lease,
requires Prentiss' prior consent as a condition to any such renewal, extension,
assignment, sublease or expansion. Prentiss shall not, without the express
written consent of Brandywine OP, in any manner change, modify, extend, renew or
terminate any Lease except as required by the terms thereof, or waive in any
material respect any of the tenant's obligations under any Lease; provided,
Leases with Prentiss' management company may be terminated on or before the
Closing Date without the prior consent of Brandywine OP. Prentiss shall not
apply all or any part of the security or

                                       24
<PAGE>

damage deposit of a tenant under any Lease to obligations of such tenant, unless
such tenant has vacated its portion of the Property as of the Closing Date.
Notwithstanding the foregoing, Brandywine OP hereby approves the new Leases
which have been entered into by Prentiss and costs associated therewith, as more
particularly described in SCHEDULE 6.4(g) hereto.

             (h) Prentiss shall cause all debts and liabilities for labor,
materials, services and equipment incurred in the construction, operation and
development of the Property, including leasehold improvements, to be promptly
paid.

             (i) Neither Prentiss nor Prentiss' managing agent shall (1) make
any agreements which shall be binding upon Brandywine OP with respect to the
Property, or (2) reduce, or cause to be reduced any rents or any other revenues
over which Prentiss has operational control.

             (j) Prentiss shall promptly deliver to Brandywine OP upon
Brandywine OP's request such reports showing the revenue and expenses of the
Property as Prentiss customarily keeps or receives internally for its own use.
(k) Except as required by the terms thereof or hereof, Prentiss shall not in any
manner change, modify, extend, renew or terminate any Operating Agreement which
would be binding on Brandywine OP with respect to the Property without the
express written consent of Brandywine OP.

             (k) Except as required by the terms thereof or hereof, Prentiss
shall not in any manner change, modify, extend, renew or terminate any Operating
Agreement which would be binding on Brandywine OP with respect to the Property
without the express written consent of Brandywine OP.

             (l) Prentiss shall promptly advise Brandywine OP of any litigation,
arbitration or administrative hearing concerning or affecting the Property of
which Prentiss obtains actual knowledge.

             (m) Prentiss shall keep all existing indebtedness, if any, current,
shall comply with the terms and provisions of all debt instruments, not modify
any such debt instruments and shall immediately send Brandywine OP copies of all
correspondence received from the holder(s) of such debt.

             (n) Prentiss shall keep the Existing Notes current, shall comply
with the terms and provisions of the Existing Notes and the Existing Liens and
shall immediately send Brandywine OP copies of all correspondence received from
any of the holders of the Existing Notes. Prentiss shall not modify any
provisions of the Existing Notes or the Existing Liens.

             (o) Prentiss shall maintain each Ground Lease in full force and
effect and shall not enter into any modification or amendment to any Ground
Lease without the prior written consent of Brandywine OP.

         6.5 NO MARKETING. Prentiss shall not market the Property for sale or
enter into discussions or negotiations with potential purchasers of the Property
unless this Agreement has been terminated pursuant to its terms.

         6.6 LEASED PROPERTY. Prentiss shall be solely responsible for all
obligations related to the Leased Property, and Brandywine OP shall have no
obligations with respect thereto. The provisions of this SECTION 6.6 shall
survive the Closing.

                                       25
<PAGE>

The foregoing covenants of Prentiss are for the benefit of Brandywine OP or its
assignee of its rights under this Agreement.

                                  ARTICLE VII.
                                     CLOSING

         7.1 CLOSING. The Closing shall occur within five (5) days after the
conditions precedent set forth in SECTIONS 5.1 AND 5.2 have been satisfied. As
more particularly described below, at the Closing the parties hereto will meet
to (i) execute all of the documents required to be delivered in connection with
the transactions contemplated hereby (the "CLOSING DOCUMENTS"), (ii) deliver the
same to Escrow Agent, and (iii) take all other action required to be taken in
respect of the transactions contemplated hereby. The Closing will occur at the
offices of the Escrow Agent. At the Closing, the Title Company shall update the
title to the Property and, provided there has been no change in the status of
title as reflected in the Title Commitment and Survey which has not been waived
by Brandywine OP pursuant to SECTION 2.4(d) hereof, and Escrow Agent shall
record the Deeds and the Assignments of Ground Leases, release and date, where
appropriate, the Closing Documents in accordance with the joint instructions of
Prentiss and Brandywine OP and shall send, by wire transfer, all sums, if any,
owing to Prentiss or Brandywine OP hereunder to Prentiss or Brandywine OP, as
applicable. At Closing, the Escrow Agent shall additionally send, by wire
transfer to Prentiss all sums owing to Prentiss hereunder. As provided herein,
the parties hereto will agree upon adjustments and prorations to certain items
which cannot be exactly determined at the Closing and will make the appropriate
adjustments with respect thereto. Possession of the Property shall be delivered
to Brandywine OP on the Closing Date, subject only to Permitted Title Exceptions
and the rights of tenants under the Leases. Notwithstanding anything herein to
the contrary, if the Closing Date does not occur by April 30, 2001, and the
provisions of Section 9.3 or 9.5 are not applicable, then either party may
terminate this Agreement by notice to the other party hereto, in which event
neither party shall have any further obligation to the other except for the
indemnities and other provisions of this Agreement which expressly survive a
termination of this Agreement, and the Deposit, less the Independent
Consideration, shall be promptly refunded to Brandywine OP.

         7.2 PRENTISS' DELIVERIES. At the Closing, Prentiss shall deliver to
Escrow Agent all of the following instruments, each of which shall have been
duly executed and, where applicable, acknowledged and/or sworn on behalf of
Prentiss and shall be dated as of the Closing Date:

             (a) The certificate required by SECTION 5.1(b) hereof.

             (b) The Deeds and Assignments of Ground Leases.

             (c) The Bill of Sale - Personal Property.

             (d) The Assignment and Assumption Agreement.

             (e) The Assignment of Leases.

             (f) An updated certified Rent Roll dated as of the date preceding
the Closing Date.

                                       26
<PAGE>

             (g) Either (i) an estoppel letter in the form of EXHIBIT C hereto
dated not more than thirty (30) days prior to the Closing Date (a) from each of
the tenants under the Leases covering 7,500 square feet or more, and (b) from
tenants leasing, in the aggregate, at least seventy-five percent (75%) of the
remainder of the Improvements, or (ii) an estoppel letter executed by Prentiss
certifying to the matters specified in EXHIBIT C hereto for any tenant which
does not execute an estoppel letter. Any estoppel letter provided by Prentiss
for a Lease pursuant to CLAUSE (ii) above shall state that Prentiss shall have
no liability thereunder if Prentiss subsequently provides to Brandywine OP an
estoppel letter in the form of EXHIBIT C from the tenant under such Lease.

             (h) Such agreements, affidavits or other documents as may be
required by the Title Company to issue the Owner's Title Policy subject only to
the Permitted Title Exceptions and to eliminate such standard exceptions and to
issue the endorsements thereto which are customarily required by institutional
investors purchasing property comparable to the Property.

             (i) An updated Title Commitment issued by the Title Company, dated
as of the date and time of Closing, subject only to the Permitted Title
Exceptions.

             (j) The FIRPTA Certificate.

             (k) All original Warranties and Guaranties in Prentiss' possession
or reasonably available to Prentiss.

             (l) To the extent in Prentiss' possession or reasonably available
to Prentiss, a valid, final and unconditional certificate of occupancy for the
Real Property and Improvements, issued by the appropriate Governmental Authority
and, if required by Applicable Laws, transferred to Brandywine OP.

             (m) The originals of the Assumed Operating Agreements, duly
assigned to Brandywine OP and with such assignment acknowledged and approved by
the other parties to such Assumed Operating Agreements to the extent required by
such Assumed Operating Agreements.

             (n) An assignment of each of the leases of the Leased Property to
Brandywine OP, together with (i) the written consent of the lessors of such
leases to such assignment, if required by such leases, and (ii) executed
originals of all such leases in Prentiss' possession or reasonably available to
Prentiss.

             (o) Executed originals of all Leases, leases of Leased Property,
permits and, to the extent in Prentiss' possession or control, Authorizations
transferred or assigned to Brandywine OP at Closing as required hereunder and
any other documents or instruments affecting the Property or the ownership and
operation thereof.

             (p) All current real estate and personal property tax bills in
Prentiss' possession or under its control.

             (q) All books, records, operating reports, appraisal reports, files
and other materials in Prentiss' possession or control which are necessary in
Brandywine OP's reasonable

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<PAGE>

discretion to maintain continuity of operation of the Property. Brandywine OP
covenants to permit Prentiss to photocopy any of the matters described in this
SUBPARAGRAPH 7.2(q) for a period of three (3) years following the Closing Date,
which covenant of Brandywine OP shall survive for such three (3) year period.

             (r) Written notice executed by Prentiss notifying all interested
parties, including, without limitation, all tenants under any Leases, that the
Property has been conveyed to Brandywine OP effective as of the Closing Date and
directing that all payments, inquiries and the like be forwarded to Brandywine
OP at the address to be provided by Brandywine OP (or as otherwise directed by
Brandywine OP).

             (s) A current UCC Report showing no financing statements by
Prentiss as Debtor covering the Property, except in favor of the holders of the
Existing Notes.

             (t) All keys to all locks on the Property in the possession of
Prentiss, together with an accounting for such keys in the possession of others.

             (u) Possession of the Property subject only to the Permitted Title
Exceptions.

             (v) Certified copies of a incumbency certificate and resolutions
authorizing the execution by Prentiss of this Agreement and all documents to be
executed by Prentiss on the Closing Date.

             (w) Estoppel letters from each owners association created pursuant
to restrictive covenants or deed restrictions affecting the Real Property
certifying that (i) the Real Property complies with such restrictive covenants
or deed restrictions, and (ii) no assessments are due and owing with respect to
the Real Property, and estoppel letters from adjoining property owners who are
parties to adjoining landowner agreements binding on any portion of the Real
Property; provided, Prentiss may execute an estoppel letter certifying to the
foregoing matters for an owners association or property owner that does not
execute any such estoppel letter, which estoppel letter shall continue in effect
unless and until the applicable estoppel letter is subsequently provided from
any such owners association or property owner.

             (x) Any other document or instrument reasonably requested by
Brandywine OP in connection with the transactions contemplated hereby.

             (y) An estoppel certificate executed by the present holders of each
of the Existing Notes substantially in the form of EXHIBIT F attached hereto.
Any and all fees and charges in connection with obtaining such written consent
or approval (specifically including, but not limited to, loan transfer fees)
shall be at Prentiss' sole cost and expense.

             (z) An estoppel certificate executed by each Ground Lessor in a
form reasonably satisfactory to Prentiss and Brandywine OP.

             (aa) The Non-Applicability Determination described in SECTION
5.1(k) hereof.

         7.3 BRANDYWINE OP'S DELIVERIES.

                                       28
<PAGE>

             (a) At the Closing, Brandywine OP shall deliver to Escrow Agent the
cash portion of the Purchase Price described in SECTION 2.2(c) hereof.

             (b) At the Closing, Brandywine OP shall deliver to Prentiss the
Assignment and Assumption Agreement, each Assignment of Ground Lease and the
Assignment of Leases, duly executed by Brandywine OP.

             (c) At the Closing, Brandywine OP shall deliver to Prentiss any
other document or instrument reasonably requested by Prentiss in connection with
the transactions contemplated hereby.

         7.4 MUTUAL DELIVERIES. At the Closing, Brandywine OP and Prentiss shall
mutually execute and deliver each to the other:

             (a) A final closing statement reflecting the adjustments and
prorations required hereunder and the allocation of income and expenses required
hereby.

             (b) Such other and further documents, papers and instruments as may
be reasonably required by the parties hereto in connection with the transactions
contemplated hereby or their respective counsel.

         7.5 CLOSING COSTS. Except as is explicitly provided in this Agreement,
each party hereto shall pay its own legal fees and expenses. Prentiss shall pay
for the costs associated with the releases of any deeds of trust, mortgages and
other financing encumbering the Property that Prentiss is to cause to be
released pursuant to this Agreement and for any costs associated with any
corrective instruments. Prentiss shall pay all costs for title searches, tax
certificates and all premiums for the issuance of the Title Policy; all costs of
providing the matters described in SECTIONS 2.4(b) AND (d) to Brandywine OP; and
one-half (1/2) of any escrow fees or similar charges of the Escrow Agent.
Brandywine OP shall pay one-half (1/2) of any escrow fees or similar charges of
the Escrow Agent. Prentiss shall pay all prepayment penalties and other costs
and expenses payable in connection with debt which Prentiss is required to
prepay on the Closing Date, and Prentiss shall pay all debt transfer and similar
fees associated with the Existing Notes and the Existing Liens. Prentiss shall
pay all assessments levied or pending against the Property as of the Closing
Date. Transfer taxes and documentary transfer stamps shall be paid in accordance
with the local customs in the States in which the Property is located. All other
expenses incurred by Prentiss or Brandywine OP with respect to the Closing shall
be borne and paid for exclusively by the party incurring same, without
reimbursement, except to the extent otherwise specifically provided herein.

         7.6 REVENUE AND EXPENSE ALLOCATIONS. All revenues (including operating
expense escalations) and expenses with respect to the Property, and applicable
to the period of time before and after Closing, determined in accordance with
sound accounting principles consistently applied, shall be allocated between
Prentiss and Brandywine OP as provided herein. Prentiss shall be entitled to all
revenue and shall be responsible for all expenses for the period of time up to
but not including the Closing Date, and Brandywine OP shall be entitled to all
revenue and shall be responsible for all expenses for the period of time from,
after and including the date of Closing. Such adjustments shall be shown on the
closing statements (with such supporting

                                       29
<PAGE>

documentation as the parties hereto may require being attached as exhibits to
the closing statements) and shall increase or decrease (as the case may be) the
cash amount payable by the parties hereto. Without limiting the generality of
the foregoing, the following items of revenue and expense shall be allocated at
Closing:

             (a) Current rents and rents payable under each Ground Lease.

             (b) Real estate and personal property taxes for the Property for
the current calendar year 2001.

             (c) Revenue and expenses under the Assumed Operating Agreements to
be assigned to and assumed by Brandywine OP.

             (d) Utility charges (including, but not limited to, charges for
water, sewer and electricity).

             (e) Municipal or other governmental improvement liens, which shall
be paid by Prentiss at Closing where the work has physically commenced, and
which shall be assumed by Brandywine OP at Closing where the work has been
authorized, but not physically commenced.

             (f) All other revenues (including CAM charges) and expenses of the
Property.

             (g) Interest on the Existing Notes.

Brandywine OP shall receive a credit for purposes of calculating closing
prorations for the total of (i) prepaid rents and (ii) unforfeited security
deposits together with interest thereon held by Prentiss under Leases.

The amount of any escrow accounts held by the holder(s) of the Existing Notes
shall be transferred to Brandywine OP by Prentiss and paid for by Brandywine OP.

Prentiss shall pay or cause to be paid all real estate taxes and installments
for special assessments (prorated to the Closing Date) for the Property due and
payable in, or deferred with respect to the years prior to, the year in which
the Closing occurs. All installments for special assessments (prorated to the
Closing Date) pending, levied or due and payable on or prior to the Closing Date
shall be paid by Prentiss on or before the Closing Date. All subdivision and
platting costs and expenses heretofore incurred by Prentiss, including, without
limitation, all subdivision exactions, fees and costs and all dedication of land
for parks and other public uses or payment of fees in lieu thereof, shall be
paid by Prentiss on or prior to the Closing Date.

In addition, if the outstanding principal balance of the Existing Notes (as that
term is defined in the Exchange Agreement of even date herewith between Prentiss
and Grande B covering certain property owned by Prentiss in Pennsylvania and New
Jersey) (the "OUTSTANDING BALANCE") is not $22,861,222.00 as of the Closing
Date, then Brandywine OP and Prentiss agree as follows: (a) if the Outstanding
Balance is greater than $22,861,222.00, Prentiss shall pay Brandywine OP in cash
at Closing the amount of the excess; and (b) if the Outstanding Balance is less
than $22,861,222.00, Brandywine OP shall pay Prentiss in cash at Closing the
difference.

                                       30
<PAGE>

If accurate allocations cannot be made at Closing because current bills are not
obtainable (as, for example, in the case of utility bills and/or real estate or
personal property taxes), the parties shall allocate such revenue or expenses at
Closing on the best available information, subject to adjustment upon receipt of
the final bill or other evidence of the applicable revenue or expense. The
obligation to make the adjustment shall survive the closing of the transaction
contemplated by this Agreement. Any revenue received or expense incurred by
Prentiss or Brandywine OP with respect to the Property after the Closing Date
shall be promptly allocated in the manner described herein and the parties shall
promptly pay or reimburse any amount due. Prentiss shall calculate and deliver
to Brandywine OP for its approval and its transmittal to tenants under Leases,
reconciliations of operating costs for the calendar year 2000, and Brandywine OP
shall inform the tenants that Prentiss prepared such reconciliations and can be
contacted to discuss any questions concerning such reconciliations. The
proration provisions of this Agreement shall survive the closing of the
transaction contemplated hereby for a period of eighteen (18) months.

         7.7 DELINQUENT RENTS. Any rents or other amounts which are delinquent
as of the Closing shall not be adjusted or prorated at Closing, but Brandywine
OP shall make a reasonable attempt to collect such amounts for the benefit of
Prentiss after the Closing; provided, however, that nothing contained herein
shall be construed to require Brandywine OP to institute any lawsuit or other
proceedings to collect such delinquent amounts. In this connection, the first
monies collected by Brandywine OP from tenants or other persons owing delinquent
rents or other amounts shall be applied to Brandywine OP's costs of collection,
then to the current rents or obligations of such person to Brandywine OP, and
the balance, if any, shall be delivered to Prentiss, to the extent of the
delinquency. Prentiss shall be permitted to bring collection suits against
tenants owing rent to Prentiss that is more than thirty (30) days in arrears;
however, Prentiss may not bring eviction actions against any tenants under any
of the Leases.

         7.8 COSTS ASSOCIATED WITH CERTAIN LEASING ACTIVITIES. Except as
otherwise expressly set forth in this SECTION 7.8, all refurbishment allowances,
tenant improvement costs and leasing commissions owing or which could become due
and owing with respect to Leases entered into on or before the Closing Date
shall be paid by Prentiss when due, and Prentiss shall indemnify and hold
harmless Brandywine OP for claims brought against the Property or Brandywine OP
arising therefrom, which indemnity shall survive the Closing. Notwithstanding
the foregoing: (i) Brandywine OP shall pay to Prentiss at the Closing an amount
equal to the cost of all (x) leasing commissions paid by Prentiss, prior to the
Closing Date, to brokers other than affiliates of Prentiss and (y) capital
improvement costs incurred and paid by Prentiss prior to the Closing Date in
completing tenant improvements pursuant to (in the case of both (x) and (y)) (a)
Leases entered into by Prentiss on or after January 1, 2001 or other Leases,
which are described on SCHEDULE 6.4(g) or which have been approved or deemed
approved by Brandywine OP pursuant to SECTION 6.4(g); (b) renewals, extensions
or expansions of existing Leases expressly requiring the approval of Prentiss as
a condition to the exercise of such options which are exercised on or after
January 1, 2001, which either are described on SCHEDULE 6.4(g) or have been
approved or deemed approved by Brandywine OP pursuant to SECTION 6.4(g); and (c)
renewals, extensions or expansions of existing Leases not requiring the approval
of Prentiss as a condition to the exercise of such options which have been
exercised on or after January 1, 2001; and (ii) Brandywine OP shall be
responsible for refurbishment allowances, tenant improvement costs and leasing
commissions shown in the Rent Roll or contained in Leases delivered pursuant to
SECTION 2.4(b)(1) hereof that have not been previously paid by Prentiss but

                                       31
<PAGE>

are payable following the Closing Date under existing Leases on or after January
1, 2001 or which are contained in Leases entered into between January 1, 2001
and the Closing Date which are described on SCHEDULE 6.4(g) or which have been
approved or deemed approved pursuant to SECTION 6.4(g) hereof. The provisions of
this SECTION 7.8 shall survive the Closing Date.

                                 ARTICLE VIII.
                               GENERAL PROVISIONS

         8.1 CONDEMNATION. In the event of any actual or threatened taking,
pursuant to the power of eminent domain, of all or any portion of the Real
Property, or any proposed sale in lieu thereof, Prentiss shall give written
notice thereof to Brandywine OP promptly after Prentiss learns or receives
notice thereof. If all or any part of the Real Property is, or is to be, so
condemned or sold, Brandywine OP shall have the right to terminate this
Agreement pursuant to SECTION 9.3 hereof. If Brandywine OP elects not to
terminate this Agreement, all proceeds, awards and other payments arising out of
such condemnation or sale (actual or threatened) shall be paid or assigned, as
applicable, to Brandywine OP at Closing and there shall be no reduction in the
Purchase Price. Prentiss shall not settle or compromise any such proceeding
without Brandywine OP's written consent. If Brandywine OP elects to terminate
this Agreement by giving Prentiss written notice thereof prior to the Closing,
the Deposit shall be promptly returned to Brandywine OP and all rights and
obligations of Prentiss and Brandywine OP hereunder (except those set forth
herein which expressly survive a termination of this Agreement) shall terminate
immediately.

         8.2 RISK OF LOSS. The risk of any loss or damage to the Property prior
to the recordation of the Deed shall remain upon Prentiss. If any such loss or
damage occurs prior to Closing which exceeds an amount equal to five percent
(5%) of the Purchase Price, Brandywine OP shall have the right to terminate this
Agreement pursuant to SECTION 9.3 hereof. If Brandywine OP elects not to
terminate this Agreement pursuant to the immediately preceding sentence or a
loss or damage occurs prior to Closing which does not exceed five percent (5%)
of the Purchase Price, all insurance proceeds and rights to proceeds arising out
of such loss or damage, less the reasonable expenses incurred in collecting such
proceeds and, to the extent payable from insurance proceeds, reasonable expenses
incurred in securing the Property following a casualty, shall be paid or
assigned, as applicable, to Brandywine OP at Closing, and Brandywine OP shall
receive as a credit against the Purchase Price in the amount of any deductibles
under the policies of insurance covering such loss or damage and there shall be
no further reduction in the Purchase Price. Prentiss shall be entitled to retain
rent loss insurance proceeds received that are attributable to periods prior to
the Closing Date. If Brandywine OP elects to terminate this Agreement pursuant
to this SECTION 8.2 by giving Prentiss written notice thereof prior to the
Closing, the Deposit shall be promptly returned to Brandywine OP and all rights
and obligations of Prentiss and Brandywine OP hereunder (except those set forth
herein which expressly survive a termination of this Agreement) shall terminate
immediately.

         8.3 BROKER. There is no real estate broker involved in this
transaction. Brandywine OP warrants and represents to Prentiss that Brandywine
OP has not dealt with any real estate broker in connection with this
transaction, nor has Brandywine OP been introduced to the Property or to
Prentiss by any real estate broker, and Brandywine OP shall indemnify Prentiss
and hold Prentiss harmless from and against any claims, suits, demands or
liabilities of

                                       32
<PAGE>

any kind or nature whatsoever arising on account of the claim of any other
person, firm or corporation to a real estate brokerage commission or a finder's
fee or a financial advisory fee as a result of having dealt with Brandywine OP,
or as a result of having introduced Brandywine OP to Prentiss or to the
Property. In like manner, Prentiss warrants and represents to Brandywine OP that
Prentiss has not dealt with any real estate broker in connection with this
transaction, nor has Prentiss been introduced to Brandywine OP by any real
estate broker, and Prentiss shall indemnify Brandywine OP and save and hold
Brandywine OP harmless from and against any claims, suits, demands or
liabilities of any kind or nature whatsoever arising on account of the claim of
any person, firm or corporation to a real estate brokerage commission or a
finder's fee or a financial advisory fee as a result of having dealt with
Prentiss in connection with this transaction. This provision shall survive any
termination of this Agreement and a closing of the transaction contemplated
hereby.

         8.4 BULK SALE. It shall be the obligation of Prentiss to comply with
any bulk sale requirements, statutes, laws, ordinances and regulations
promulgated with respect thereto, if any, in the State in which the Property is
located, or in or by any governmental entity having jurisdiction with respect
thereto, and to provide proof of such compliance or proof that no such
compliance is required, to Brandywine OP, at or prior to Closing. In any event,
Prentiss shall indemnify Brandywine OP and save and hold Brandywine OP harmless
from and against any claims, suits, demands, liabilities or obligations of any
kind or nature whatsoever, including all costs of defending same, and reasonable
attorneys' fees paid or incurred in connection therewith, arising out of or
relating to any claim made by any third party or any liability asserted by any
third party that any applicable bulk sales law or like statute has not been
complied with. The provisions of this Section shall survive the Closing of the
transaction contemplated hereby.

                                  ARTICLE IX.
            LIABILITY OF BRANDYWINE OP; INDEMNIFICATION BY PRENTISS;
                           DEFAULT; TERMINATION RIGHTS

         9.1 LIABILITY OF BRANDYWINE OP. Except for obligations expressly
assumed or agreed to be assumed by Brandywine OP hereunder, Brandywine OP is not
assuming any obligations of Prentiss or any liability for claims arising out of
any act, omission or occurrence which occurs, accrues or arises prior to the
Closing Date, and Prentiss hereby indemnifies and holds Brandywine OP harmless
from and against any and all claims, costs, penalties, damages, losses,
liabilities and expenses (including reasonable attorneys' fees) that may at any
time be incurred by Brandywine OP as a result of (a) obligations of Prentiss not
expressly assumed or agreed to be assumed by Brandywine OP hereunder, or (b)
acts, omissions or occurrences which occur, accrue or arise prior to the Closing
Date. Brandywine OP hereby indemnifies and holds Prentiss harmless from and
against any and all claims, costs, penalties, damages, losses, liabilities and
expenses (including reasonable attorneys' fees) that may at any time be incurred
by Prentiss as a result of acts, omissions or occurrences relating to the
Property arising and accruing from and after the Closing Date. The provisions of
this Section shall survive the Closing of the transaction contemplated hereby.

         9.2 INDEMNIFICATION BY PRENTISS. Prentiss hereby indemnifies and holds
Brandywine OP and Brandywine OP's officers, partners, directors, shareholders,
agents and employees (collectively, the "INDEMNIFIED PARTIES") harmless from and
against any and all

                                       33
<PAGE>

claims, costs, penalties, damages, losses, liabilities and expenses (including
reasonable attorneys' fees) that may at any time be incurred by Brandywine OP,
whether incurred before or after Closing, as a result of any inaccuracy or
breach by Prentiss of any of its representations, warranties, covenants or
obligations set forth herein or in any other document delivered by Prentiss
pursuant hereto except for any breach or inaccuracy of any representation or
warranty as to which Prentiss has given Brandywine OP written notice prior to
Closing of the untruth or inaccuracy or of which Brandywine OP otherwise had
actual knowledge prior to the Closing and nevertheless elected to consummate the
Closing; provided, however, the foregoing knowledge limitation on Prentiss'
indemnity shall not limit Brandywine OP's remedy described in SECTION 9.3(a)(ii)
hereof or in the last sentence of SECTION 9.3 hereof. The provisions of this
Section shall survive the Closing of the transaction contemplated hereby as
provided in SECTION 10.11 hereof, and shall, following any assignment of this
Agreement by Brandywine OP, continue in favor of the Indemnified Parties of the
original Brandywine OP hereunder as well the Indemnified Parties of any assignee
during said survival period.

         9.3 DEFAULT BY PRENTISS/FAILURE OF CONDITIONS PRECEDENT. If any
condition set forth herein for the benefit of Brandywine OP cannot or will not
be satisfied prior to Closing, or upon the occurrence of any other event that
would entitle Brandywine OP to terminate this Agreement and its obligations
hereunder, and if Prentiss fails to cure any such matter or satisfy that
condition within ten (10) business days after notice thereof from Brandywine OP
(or such other time period as may be explicitly provided for herein), Brandywine
OP, at its option, may elect (a) to terminate this Agreement, in which event (i)
the Deposit, less the Independent Consideration, shall be promptly returned to
Brandywine OP, (ii) if the condition which has not been satisfied is a breach of
a representation, warranty or covenant known by Prentiss to have been inaccurate
or misleading when made, then Prentiss shall be obligated upon demand to
reimburse Brandywine OP for Brandywine OP's actual out-of-pocket inspection,
financing and other costs related to Brandywine OP's entering into this
Agreement, inspecting the Property and preparing for a Closing of the
transaction contemplated hereby, including, without limitation, Brandywine OP's
attorneys' fees incurred in connection with the preparation, negotiation and
execution of this Agreement and in connection with Brandywine OP's due diligence
review, audits and preparation for a Closing up to an aggregate amount equal to
$100,000.00; provided, the foregoing shall not limit or include the sums which
may be payable by Prentiss pursuant to SECTION 9.6 below, and (iii) all other
rights and obligations of Prentiss and Brandywine OP hereunder (except those set
forth herein which expressly survive a termination of this Agreement) shall
terminate immediately; (b) elect to proceed to Closing; or (c) seek to enforce
Prentiss' obligations hereunder by specific performance. If Brandywine OP elects
to proceed to Closing and there is either a misrepresentation or breach of a
warranty by Prentiss (other than a breach of a representation or warranty of
which Brandywine OP had actual knowledge prior to the Closing and nevertheless
elected to consummate the Closing) or the breach of a covenant by Prentiss or a
failure by Prentiss to perform its obligations hereunder first discovered by
Brandywine OP after the Closing Date, Brandywine OP shall retain all remedies
accruing as a result thereof, including, but not limited to, the remedy of
specific performance of Prentiss' covenants and obligations and the remedy of
the recovery of all reasonable damages resulting from Prentiss' breach of
warranty or covenant. Notwithstanding the foregoing, if the condition which has
not been satisfied is a breach of one or more representations and warranties by
Prentiss and/or Prentiss Properties Limited, Inc. ("PPL") in this Agreement
and/or in any of the other documents executed of even date herewith among
Prentiss, PPL, Brandywine OP or any of

                                       34
<PAGE>

their respective affiliates (the "OTHER DOCUMENTS"), Brandywine OP has elected
to proceed to Closing, and Brandywine OP can reasonably quantify the damage
resulting from such breach of representations and warranties with reasonable
support for such calculation of damages, then (i) if the aggregate damage is no
greater than $150,000.00 (the "FIRST THRESHOLD LEVEL"), then Prentiss shall have
no obligation to either cure such breaches of representations and warranties or
pay Brandywine OP at Closing in the event Brandywine OP elects to close the
transaction described in this Agreement and the Other Documents; (ii) if such
aggregate damage is greater than the First Threshold Level but less than
$1,500,000.00, then Prentiss must prior to the Closing Date either cure such
breaches of representations and warranties to the reasonable satisfaction of
Brandywine OP or Prentiss shall pay Brandywine OP at the Closing an amount equal
to the actual damages as reasonably determined by Brandywine OP as aforesaid,
less the First Threshold Level; and (iii) in the event the aggregate damages
resulting from such breaches of representations and warranties would exceed
$1,500,000.00, then Brandywine OP may either (A) terminate this Agreement and
the Other Documents, in which event the Deposit (less the Independent
Consideration) shall be promptly refunded, or (B) Brandywine OP may close the
transaction as described in this Agreement and the other Transaction Documents
and Brandywine OP shall be paid by Prentiss the amount of $1,350,000.00, which
amount shall be the maximum aggregate amount payable by Prentiss and/or PPL
under the last sentence of SECTION 9.3 of this Agreement and all of the Other
Documents.

         9.4 INDEMNIFICATION BY BRANDYWINE OP. Brandywine OP hereby indemnifies
and holds Prentiss harmless from and against any and all claims, costs,
penalties, damages, losses, liabilities and expenses (including reasonable
attorneys' fees) that may at any time be incurred by Prentiss, whether incurred
before or after Closing, as a result of any inaccuracy or breach by Brandywine
OP of any of its representations, warranties, covenants or obligations set forth
herein or in any other document delivered by Brandywine OP pursuant hereto
except for any breach or inaccuracy of any representation or warranty as to
which Brandywine OP has given Prentiss written notice prior to Closing of the
untruth or inaccuracy or of which Prentiss otherwise had actual knowledge prior
to the Closing and nevertheless elected to consummate the Closing. The
provisions of this Section shall survive the Closing of the transaction
contemplated hereby for the period described in SECTION 10.11 hereof.

         9.5 DEFAULT BY BRANDYWINE OP/FAILURE OF CONDITIONS PRECEDENT. If any
condition set forth herein for the benefit of Prentiss (other than a default by
Brandywine OP) cannot or will not be satisfied prior to Closing, and if
Brandywine OP fails to satisfy that condition within ten (10) business days
after notice thereof from Prentiss (or such other time period as may be
explicitly provided for herein), Prentiss may, at its option, elect either (a)
to terminate this Agreement in which event the Deposit shall be promptly
returned to Brandywine OP and the parties hereto shall be released from all
further obligations hereunder except those which expressly survive a termination
of this Agreement, or (b) to waive its right to terminate, and instead, to
proceed to Closing. If, prior to Closing, Brandywine OP defaults in performing
any of its obligations under this Agreement (including its obligation to
purchase the Property), and Brandywine OP fails to cure any such default within
ten (10) business days after notice thereof from Prentiss, then Prentiss' sole
remedy for such default shall be either (i) to terminate this Agreement and
retain the Deposit or (ii) to pursue the remedy of specific performance
compelling Brandywine OP to purchase the Property pursuant to the provisions of
this Agreement.

                                       35
<PAGE>

         9.6 COSTS AND ATTORNEYS' FEES. In the event of any litigation or
dispute between the parties arising out of or in any way connected with this
Agreement, resulting in any litigation, then the prevailing party in such
litigation shall be entitled to recover its costs of prosecuting and/or
defending same, including, without limitation, reasonable attorneys' fees at
trial and all appellate levels. The provisions of this Section shall survive the
Closing of the transaction contemplated hereby.

         9.7 LIMITATION OF LIABILITY. Notwithstanding anything herein to the
contrary, except in the case of fraud by either party, the liability of each
party hereto resulting from the breach or default by either party shall be
limited to actual damages incurred by the injured party and except in the case
of fraud by either party, the parties hereto hereby waive their rights to
recover from the other party consequential, punitive, exemplary, and speculative
damages. The provisions of this SECTION 9.7 shall survive the Closing of the
transaction contemplated hereby.

                                   ARTICLE X.
                            MISCELLANEOUS PROVISIONS

         10.1 COMPLETENESS; MODIFICATION. This Agreement constitutes the entire
agreement between the parties hereto with respect to the transactions
contemplated hereby and supersede all prior discussions, understandings,
agreements and negotiations between the parties hereto. This Agreement may be
modified only by a written instrument duly executed by the parties hereto. Any
waiver of rights under this Agreement shall be effective only if in writing and
duly executed and delivered by the party against whom such waiver is asserted.

         10.2 ASSIGNMENTS. Brandywine OP may assign its rights hereunder without
the consent of Prentiss to any affiliate of Brandywine OP, in which event,
except as otherwise specified herein, such assignee shall be the "BRANDYWINE OP"
hereunder; however, any such assignment shall not relieve the original
Brandywine OP of its obligations under this Agreement, including specifically
the obligation to close the purchase of the Property in accordance with this
Agreement as though there were no assignment.

         10.3 SUCCESSORS AND ASSIGNS. This Agreement shall bind and inure to the
benefit of the parties hereto and their respective successors and assigns.

         10.4 DAYS. If any action is required to be performed, or if any notice,
consent or other communication is given, on a day that is a Saturday or Sunday
or a legal holiday in the jurisdiction in which the action is required to be
performed or in which is located the intended recipient of such notice, consent
or other communication, such performance shall be deemed to be required, and
such notice, consent or other communication shall be deemed to be given, on the
first business day following such Saturday, Sunday or legal holiday. Unless
otherwise specified herein, all references herein to a "DAY" or "DAYS" shall
refer to calendar days and not business days.

         10.5 GOVERNING LAW. This Agreement and all documents referred to herein
shall be governed by and construed and interpreted in accordance with the laws
of the State of Delaware.

         10.6 COUNTERPARTS. To facilitate execution, this Agreement may be
executed in as many counterparts as may be required. It shall not be necessary
that the signature on behalf of

                                       36
<PAGE>

both parties hereto appear on each counterpart hereof. All counterparts hereof
shall collectively constitute a single agreement.

         10.7 SEVERABILITY. If any term, covenant or condition of this
Agreement, or the application thereof to any person or circumstance, shall to
any extent be invalid or unenforceable, the remainder of this Agreement, or the
application of such term, covenant or condition to other persons or
circumstances, shall not be affected thereby, and each term, covenant or
condition of this Agreement shall be valid and enforceable to the fullest extent
permitted by law.

         10.8 NOTICES. All notices, requests, demands and other communications
hereunder shall be in writing and shall be delivered by hand, transmitted by
facsimile transmission, sent prepaid by Federal Express (or a comparable
overnight delivery service) or sent by the United States mail, certified,
postage prepaid, return receipt requested, at the addresses and with such copies
as designated below. Any notice, request, demand or other communication
delivered or sent in the manner aforesaid shall be deemed given or made (as the
case may be) when actually delivered to the intended recipient.

         If to Brandywine OP:     c/o Brandywine Realty Trust
                                  14 Campus Boulevard, Suite 100
                                  Newtown Square, PA  19073-3780
                                  Attn: Brad A. Molotsky, General Counsel
                                  Fax No.: 610-325-4628

         If to Prentiss:          Prentiss Properties Acquisition Partners, L.P.
                                  3860 West Northwest Highway, Suite 400

                                  Dallas, Texas  75220
                                  Attn.: J. Kevan Dilbeck, General Counsel
                                  Fax No.: (214) 350-2409

         With a copy to:          Akin, Gump, Strauss, Hauer & Feld, L.L.P.
                                  1700 Pacific Avenue, Suite 4100
                                  Dallas, Texas  75201-4675
                                  Attn.:  Randall M. Ratner, P.C.
                                  Fax No.:  (214) 969-4343

         If to Escrow Agent:      Chicago Title Insurance Company
                                  2001 Bryan Street, Suite 1700
                                  Dallas, Texas  75201
                                  Attn.:  Ellen Schwab
                                  Fax No.:  (214) 965-1629

or to such other address as the intended recipient may have specified in a
notice to the other party. Any party hereto may change its address or designate
different or other persons or entities to receive copies by notifying the other
party and Escrow Agent in a manner described in this Section.

                                       37
<PAGE>

         10.9 ESCROW AGENT. Escrow Agent referred to in the definition thereof
contained in SECTION 1.1 hereof has agreed to act as such for the convenience of
the parties without fee or other charges for such services as Escrow Agent.
Escrow Agent shall not be liable: (a) to any of the parties for any act or
omission to act except for its own willful misconduct; (b) for any legal effect,
insufficiency, or undesirability of any instrument deposited with or delivered
by Escrow Agent or exchanged by the parties hereunder, whether or not Escrow
Agent prepared such instrument; (c) for any loss or impairment of funds that
have been deposited in escrow while those funds are in the course of collection,
or while those funds are on deposit in a financial institution, if such loss or
impairment results from the failure, insolvency or suspension of a financial
institution; (d) for the expiration of any time limit or other consequence of
delay, unless a properly executed written instruction, accepted by Escrow Agent,
has instructed Escrow Agent to comply with said time limit; or (e) for the
default, error, action or omission of either party to the escrow. Escrow Agent,
in its capacity as escrow agent, shall be entitled to rely on any document or
paper received by it, believed by such Escrow Agent, in good faith, to be bona
fide and genuine. In the event of any dispute as to the disposition of the
Deposit or any other monies held in escrow, or of any documents held in escrow,
Escrow Agent may, if such Escrow Agent so elects, interplead the matter by
filing an interpleader action in a court of general jurisdiction in the county
or circuit where the Real Property is located (to the jurisdiction of which both
parties do hereby consent), and pay into the registry of the court the Deposit,
or deposit any such documents with respect to which there is a dispute in the
Registry of such court, whereupon such Escrow Agent shall be relieved and
released from any further liability as Escrow Agent hereunder. Escrow Agent
shall not be liable for Escrow Agent's compliance with any legal process,
subpoena, writ, order, judgment and decree of any court, whether issued with or
without jurisdiction, and whether or not subsequently vacated, modified, set
aside or reversed.

         10.10 INCORPORATION BY REFERENCE. All of the exhibits attached hereto
are by this reference incorporated herein and made a part hereof.

         10.11 SURVIVAL. All of the representations, warranties, covenants and
agreements of Prentiss and Brandywine OP made in, or pursuant to, this Agreement
shall survive Closing through the period ending twelve (12) months thereafter
and shall not merge into the Deed or any other document or instrument executed
and delivered in connection herewith; provided, the covenants in the last
sentence of SECTION 2.4(b) and SECTION 7.6 shall survive for the time periods
described in such Sections, and the covenants in SECTIONS 6.6 AND 7.8 and the
indemnities in this Agreement shall have an unlimited survival period. In the
event a claim for indemnity is asserted in good faith prior to the expiration of
the applicable survival period, the claim may be asserted and the indemnity
shall continue notwithstanding the expiration of the survival period.

         10.12 FURTHER ASSURANCES. Prentiss and Brandywine OP each covenant and
agree to sign, execute and deliver, or cause to be signed, executed and
delivered, and to do or make, or cause to be done or made, upon the written
request of the other party, any and all agreements, instruments, papers, deeds,
acts or things, supplemental, confirmatory or otherwise, as may be reasonably
required by either party hereto for the purpose of or in connection with
consummating the transactions described herein. Prentiss agrees to promptly
correct any defect, error or omission which may be discovered in the contents of
this Agreement or in any of the Exhibits or Schedules hereto.

                                       38
<PAGE>

         10.13 NO PARTNERSHIP. This Agreement does not and shall not be
construed to create a partnership, joint venture or any other relationship
between the parties hereto except the relationship of Prentiss and Brandywine OP
specifically established hereby.

         10.14 TIME OF ESSENCE. Time is of the essence with respect to every
provision hereof.

         10.15 SIGNATORY EXCULPATION. The signatory(ies) for Prentiss and
Brandywine OP are executing this Agreement in his/their capacity as
representative of Prentiss and Brandywine OP, respectively, and not individually
and, therefore, shall have no personal or individual liability of any kind in
connection with this Agreement and the transactions contemplated by it. No
recourse shall be had for any obligation of Prentiss or Brandywine OP under this
Agreement or under any document executed in connection herewith or pursuant
hereto, or for any claim based thereon or otherwise in respect thereof, against
any past, present or future trustee, shareholder, officer or employee of
Brandywine Realty Trust, Prentiss Properties Trust, Prentiss or Brandywine OP,
whether by virtue of any statute or rule of law, or by the enforcement of any
assessment or penalty or otherwise, all such liability being expressly waived
and released by the parties hereto and all parties claiming by, through or under
them.

         10.16 RULES OF CONSTRUCTION. The following rules shall apply to the
construction and interpretation of this Agreement:

             (a) Singular words shall connote the plural number as well as the
singular and vice versa, and the masculine shall include the feminine and the
neuter.

             (b) All references herein to particular articles, sections,
subsections, clauses or exhibits are references to articles, sections,
subsections, clauses or exhibits of this Agreement.

             (c) The table of contents and headings contained herein are solely
for convenience of reference and shall not constitute a part of this Agreement
nor shall they affect its meaning, construction or effect.

             (d) Each party hereto and its counsel have reviewed and revised (or
requested revisions of) this Agreement and have participated in the preparation
of this Agreement, and therefore any usual rules of construction requiring that
ambiguities are to be resolved against a particular party shall not be
applicable in the construction and interpretation of this Agreement or any
exhibits hereto.

             (e) As used herein, the term or phrases "EFFECTIVE DATE," "DATE OF
THIS AGREEMENT" or "DATE HEREOF" shall mean the first date Escrow Agent is in
receipt of this Agreement executed by Prentiss and Brandywine OP.

         10.17 LIKE-KIND EXCHANGE. Prentiss agrees to cooperate reasonably with
Brandywine OP in effecting an exchange transaction which includes the Property,
pursuant to Section 1031 of the United States Internal Revenue Code, provided
that any such exchange transaction, and the related documentation, shall: (a) be
at the sole cost and expense of Brandywine OP; (b) not require Prentiss to
execute any contract, make any commitment, or incur any obligations, contingent
or otherwise, to third parties; (c) not delay the Closing; (d) not

                                       39
<PAGE>

include Prentiss becoming involved in a transaction with a third party; and (e)
not otherwise be contrary to or inconsistent with the terms of this Agreement.

         10.18 SEC REPORTING (8-K) REQUIREMENTS. For the period of time
commencing on the date hereof and continuing through the second anniversary of
the Closing Date, and without limitation of other document production otherwise
required of Prentiss hereunder, Prentiss shall, from time to time, upon
reasonable advance written notice from Brandywine OP, provide Brandywine OP and
its representatives, with access to all financial and other information
pertaining to the period of Prentiss' ownership and operation of the Property,
which information is relevant and reasonably necessary, in the opinion of
outside, third party accountants (the "ACCOUNTANTS") for Brandywine OP, to
enable Brandywine OP and its Accountants to prepare financial statements in
compliance with any or all of (a) Rule 3-05 or 3-14 of Regulation S-X of the
Securities and Exchange Commission (the "COMMISSION"), as applicable; (b) any
other rule issued by the Commission and applicable to Brandywine OP or
Brandywine Realty Trust ("BRANDYWINE"); and (c) any registration statement,
report or disclosure statement filed with the Commission by Brandywine; and a
representation letter, signed by the individual(s) responsible for Prentiss'
financial reporting, as prescribed by generally accepted auditing standards
promulgated by the Auditing Standards Division of the American Institute of
Certified Public Accountants, which representation letter may be required by the
Accountants in order to render an opinion concerning Brandywine OP's or
Brandywine's financial statements.

                                       40
<PAGE>

         IN WITNESS WHEREOF, Prentiss and Brandywine OP have caused this
Agreement to be executed in their names by their respective duly authorized
representatives.

                                 BRANDYWINE OP:

                                 BRANDYWINE OPERATING PARTNERSHIP, L.P., a
                                 Delaware limited partnership

                                 By: /s/ Gerard H. Sweeney, a_______________,
                                         its general partner

                                         By:  /s/ Gerard H. Sweeney
                                         Name:  Gerard H. Sweeney
                                         Title:  President & CEO

                                         Date of Execution:  March 14, 2001

                                 GRANDE B:

                                 BRANDYWINE GRANDE B, L.P., a Delaware limited
                                 partnership

                                 By: BRANDYWINE GRANDE B CORP., a Delaware
                                     corporation, its general partner

                                     By:  /s/ Gerard H. Sweeney
                                     Name:  Gerard H. Sweeney
                                     Title:  President & CEO

                                     Date of Execution:  March 14, 2001

                                       41
<PAGE>

                                 PRENTISS:

                                 PRENTISS PROPERTIES ACQUISITION PARTNERS, L.P.,
                                 a Delaware limited partnership

                                 By: Prentiss Properties I, Inc., a Delaware
                                     corporation, its general partner

                                     By:  /s/ Thomas F. August
                                     Name:  Thomas F. August
                                     Title:  President & CEO

                                     Date of Execution:  March 14, 2001

                             RECEIPT OF ESCROW AGENT

         Chicago Title Insurance Company, as Escrow Agent, acknowledges receipt
of the sum of $200,050.00 by check or by wire transfer, from Brandywine OP as
described in SECTION 2.3 of the foregoing Agreement of Purchase and Sale, said
check or wire transfer to be held pursuant to the terms and provisions of said
Agreement.

         DATED this _____ day of __________, 2001.

                                           CHICAGO TITLE INSURANCE COMPANY

                                           By:
                                              ----------------------------------
                                           Name:
                                                --------------------------------
                                           Title:
                                                 -------------------------------

                                       42<PAGE>

                                                                    Exhibit 10.4
                                                           PA - ENTITY TRANSFERS

                         AGREEMENT OF PURCHASE AND SALE

                                      among

                 PRENTISS PROPERTIES ACQUISITION PARTNERS, L.P.,
                         a Delaware limited partnership

                                  ("PRENTISS"),

                       PRENTISS PROPERTIES LIMITED, INC.,
                             a Delaware corporation

                                     ("PPL")

                                       and

                     BRANDYWINE OPERATING PARTNERSHIP, L.P.,
                         a Delaware limited partnership

                                ("BRANDYWINE OP")
<PAGE>

                                TABLE OF CONTENTS

                                                                            Page

ARTICLE I. DEFINITIONS........................................................2
     1.1   Definitions........................................................2
ARTICLE II. PURCHASE AND SALE; DEPOSIT; PAYMENT OF PURCHASE PRICE;
STUDY PERIOD; ASSIGNMENTS SUBJECT TO EXISTING NOTES AND LIENS.................9
     2.1   Purchase and Sale..................................................9
     2.2   Payment of Purchase Price; Assignments Subject to Existing Notes
           and Liens..........................................................9
     2.3   Deposit...........................................................10
     2.4   Study Period......................................................11
ARTICLE III. PRENTISS' REPRESENTATIONS AND WARRANTIES........................15
     3.1   Organization and Power............................................15
     3.2   Authorization, Execution and Disclosure...........................16
     3.3   Non-contravention.................................................16
     3.4   No Special Taxes..................................................16
     3.5   Compliance with Existing Laws and Restrictive Covenants...........17
     3.6   Personal Property.................................................17
     3.7   Operating Agreements..............................................17
     3.8   Condemnation Proceedings; Roadways................................17
     3.9   Actions or Proceedings............................................18
     3.10  Bankruptcy........................................................18
     3.11  Hazardous Substances..............................................18
     3.12  Parties in Possession.............................................19
     3.13  Leases............................................................19
     3.14  Leased Property...................................................19
     3.15  No Unpaid Charges; Financial Statements...........................19
     3.16  Condition of Improvements.........................................20
     3.17  Access............................................................20
     3.18  No Commitments....................................................20
     3.19  None of the Partnerships nor Prentiss Is a "Foreign Person".......20
     3.20  Leasing Commissions...............................................20
     3.21  Other Agreements..................................................20
     3.22  Existing Secured Indebtedness.....................................21
     3.23  Employment on "At-Will" Basis.....................................21
     3.24  Additional Representations and Warranties with Respect to
           the Partnerships..................................................21
     3.25  Representations and Warranties of PPL.............................22
     3.26  LIMITATIONS ON REPRESENTATIONS AND WARRANTIES.....................23
ARTICLE IV. BRANDYWINE OP'S REPRESENTATIONS AND WARRANTIES...................25
     4.1   Organization and Power............................................25
     4.2   Non-contravention.................................................25
     4.3   Litigation........................................................25
     4.4   Bankruptcy........................................................25
     4.5   Authorization, Execution and Disclosure...........................25
ARTICLE V. CONDITIONS PRECEDENT..............................................26

                                       i
<PAGE>

     5.1   As to Brandywine OP's Obligations.................................26
     5.2   As to Prentiss' Obligations.......................................27
ARTICLE VI. COVENANTS OF PRENTISS............................................28
     6.1   Operating Agreements..............................................28
     6.2   Warranties and Guaranties.........................................28
     6.3   Insurance.........................................................28
     6.4   Operation of Property Prior to Closing............................29
     6.5   No Marketing......................................................30
     6.6   Put/Call Agreement................................................31
     6.7   Tax Returns.......................................................31
     6.8   Ground Lessor Estoppels...........................................32
     6.9   Leased Property...................................................32
ARTICLE VII. CLOSING.........................................................32
     7.1   Closing...........................................................32
     7.2   Prentiss' Deliveries..............................................32
     7.3   Brandywine OP's Deliveries........................................35
     7.4   Mutual Deliveries.................................................35
     7.5   Closing Costs.....................................................35
     7.6   Revenue and Expense Allocations...................................36
     7.7   Delinquent Rents..................................................37
     7.8   Costs Associated with Certain Leasing Activities..................38
ARTICLE VIII. GENERAL PROVISIONS.............................................38
     8.1   Condemnation......................................................38
     8.2   Risk of Loss......................................................39
     8.3   Broker............................................................39
ARTICLE IX. LIABILITY OF BRANDYWINE OP; INDEMNIFICATION BY PRENTISS;
DEFAULT; TERMINATION RIGHTS..................................................40
     9.1   Liability of Brandywine OP........................................40
     9.2   Indemnification by Prentiss.......................................40
     9.3   Default by Prentiss/Failure of Conditions Precedent...............41
     9.4   Indemnification by Brandywine OP..................................42
     9.5   Default by Brandywine OP/Failure of Conditions Precedent..........42
     9.6   Costs and Attorneys' Fees.........................................42
     9.7   Limitation of Liability...........................................43
ARTICLE X. MISCELLANEOUS PROVISIONS..........................................43
     10.1  Completeness; Modification........................................43
     10.2  Assignments.......................................................43
     10.3  Successors and Assigns............................................43
     10.4  Days..............................................................43
     10.5  Governing Law.....................................................44
     10.6  Counterparts......................................................44
     10.7  Severability......................................................44
     10.8  Notices...........................................................44
     10.9  Escrow Agent......................................................45
     10.10 Incorporation by Reference........................................45
     10.11 Survival..........................................................45

                                       ii
<PAGE>

     10.12 Further Assurances................................................46
     10.13 No Partnership....................................................46
     10.14 Time of Essence...................................................46
     10.15 Signatory Exculpation.............................................46
     10.16 Rules of Construction.............................................46
     10.17 SEC Reporting (8-K) Requirements..................................47

EXHIBITS
Exhibit A -       Land
Exhibit B -       Description of Ground Leases
Exhibit C -       Tenant's Estoppel Certificate
Exhibit D -       Excluded Tangible Personal Property
Exhibit E -       Existing Notes and Existing Liens
Exhibit F -       Form of Lender Estoppel Certificate
Exhibit G -       Form of Amended and Restated Partnership
Exhibit H -       Capital Accounts of Prentiss in the Partnerships

SCHEDULES
Schedule 3.7      Operating Agreements
Schedule 3.13     Rent Roll and Accounts Receivable Report
Schedule 3.20     Outstanding Leasing Commissions
Schedule 6.4(g)   Approved New Leases
Schedule 6.6      Allocation of Aggregate Price among Retained Interests

                                      iii
<PAGE>

                         AGREEMENT OF PURCHASE AND SALE

     THIS AGREEMENT OF PURCHASE AND SALE (this "AGREEMENT") is made as of this
____ day of March, 2001, among PRENTISS PROPERTIES ACQUISITION PARTNERS, L.P., a
Delaware limited partnership ("PRENTISS"), PRENTISS PROPERTIES LIMITED, INC., a
Delaware corporation ("PPL") and BRANDYWINE OPERATING PARTNERSHIP, L.P., a
Delaware limited partnership ("BRANDYWINE OP").

                             R E C I T A T I O N S:

     A. 111 Arrandale Boulevard Associates, L.P. ("111 ARRANDALE") is the owner
of a fee estate located in the Commonwealth of Pennsylvania that is identified
as the 111 Arrandale Land on EXHIBIT A attached hereto (the "111 ARRANDALE
LAND"), 440 Creamery Way Associates, L.P. ("440 CREAMERY WAY") is the owner of a
fee estate located in the Commonwealth of Pennsylvania that is identified as the
440 Creamery Way Land on EXHIBIT A attached hereto (the "440 CREAMERY WAY
LAND"), 442 Creamery Way Associates, L.P. ("442 CREAMERY WAY") is the owner of a
fee estate located in the Commonwealth of Pennsylvania that is identified as the
442 Creamery Way Land on EXHIBIT A attached hereto (the "442 CREAMERY WAY
LAND"), 481 John Young Way Associates, L.P. ("481 JOHN YOUNG") is the owner of a
fee estate located in the Commonwealth of Pennsylvania that is identified as the
481 John Young Land on EXHIBIT A attached hereto (the "481 JOHN YOUNG LAND"),
and 100 Arrandale Boulevard Associates, L.P. ("100 ARRANDALE") is the owner of a
fee estate located in the Commonwealth of Pennsylvania that is identified as the
100 Arrandale Land on EXHIBIT A attached hereto (the "100 ARRANDALE LAND").

     B. Southpoint Land Holdings, Inc. ("SOUTHPOINT INC.") is the ground lessor
under the ground leases identified on EXHIBIT B attached hereto as the
Southpoint Ground Leases, and Valleybrooke Land Holdings, Inc. ("VALLEYBROOKE
INC.") is the ground lessor under the ground leases identified on EXHIBIT B
attached hereto as the Valleybrooke Ground Leases.

     C. Prentiss owns an eighty-eight percent (88%) limited partnership interest
and a one percent (1%) general partnership interest in each of 111 Arrandale,
100 Arrandale, 440 Creamery Way, 442 Creamery Way, and 481 John Young (which
interests are referred to in the Partnership Agreements (as hereinafter defined)
as the "CAPITAL PERCENTAGE INTERESTS"). In addition, Prentiss owns a ninety-nine
percent (99%) "Profit Percentage Interest" in each of 111 Arrandale, 100
Arrandale, 440 Creamery Way, 442 Creamery Way and 481 John Young.

     D. PPL owns 89 of the 100 outstanding shares of common stock in each of
Southpoint Inc. and Valleybrooke Inc., and PPL has the right to require that the
holders of the remaining 11 shares of outstanding common stock in each of
Southpoint Inc. and Valleybrooke Inc. sell such shares to PPL upon demand
pursuant to a Put and Call Option Agreement for Remaining Shares dated as of
October 22, 1997 (the "OPTION AGREEMENT") among PPL, Henry C. Gulbrandsen, Jr.,
Peter O. Hausman and Timothy J. Weber (Gulbrandsen, Hausman and Weber are
collectively called the "SHAREHOLDERS").

     E. Brandywine OP (or its designee) is desirous of acquiring (i) from
Prentiss certain of Prentiss' partnership interests in 111 Arrandale, 100
Arrandale, 440 Creamery Way,

                                       1
<PAGE>

442 Creamery Way and 481 John Young, and (ii) from PPL 78 shares of common stock
in each of Southpoint Inc. and Valleybrooke Inc., and Prentiss and PPL are
desirous of transferring such partnership interests and common stock to
Brandywine OP (or its designee), for the Purchase Price and upon the terms and
conditions hereinafter set forth.

     NOW, THEREFORE, in consideration of the foregoing premises and in
consideration of the mutual covenants, promises and undertakings of the parties
hereinafter set forth, and for other good and valuable consideration, the
receipt and sufficiency of which is hereby acknowledged by the parties, it is
agreed:

                                   ARTICLE I.
                                   DEFINITIONS

     1.1   DEFINITIONS. The following terms shall have the indicated meanings:

           "ACT OF BANKRUPTCY" shall mean if a party hereto or any general
partner thereof shall (a) apply for or consent to the appointment of, or the
taking of possession by, a receiver, custodian, trustee or liquidator of itself
or of all or a substantial part of its property, (b) admit in writing its
inability to pay its debts as they become due, (c) make a general assignment for
the benefit of its creditors, (d) file a voluntary petition or commence a
voluntary case or proceeding under the Federal Bankruptcy Code (as now or
hereafter in effect), (e) be adjudicated a bankrupt or insolvent, (f) file a
petition seeking to take advantage of any other law relating to bankruptcy,
insolvency, reorganization, winding-up or composition or adjustment of debts,
(g) fail to controvert in a timely and appropriate manner, or acquiesce in
writing to, any petition filed against it in an involuntary case or proceeding
under the Federal Bankruptcy Code (as now or hereafter in effect), or (h) take
any corporate or partnership action for the purpose of effecting any of the
foregoing; or if a proceeding or case shall be commenced, without the
application or consent of a party hereto or any general partner thereof, in any
court of competent jurisdiction seeking (1) the liquidation, reorganization,
dissolution or winding-up, or the composition or readjustment of debts, of such
party or general partner, (2) the appointment of a receiver, custodian, trustee
or liquidator for such party or general partner or all or any substantial part
of its assets, or (3) other similar relief under any law relating to bankruptcy,
insolvency, reorganization, winding-up or composition or adjustment of debts,
and such proceeding or case shall continue undismissed for a period of ninety
(90) consecutive days; or an order (including an order for relief entered in an
involuntary case under the Federal Bankruptcy Code, as now or hereafter in
effect) judgment or decree approving or ordering any of the foregoing shall be
entered and continue unstayed and in effect, for a period of ninety (90)
consecutive days.

           "ADDITIONAL RETAINED INTERESTS" shall mean the entire right, title
and interest of each of Gorman and Knauer in each of the Partnerships (which
interest, in aggregate, is comprised of an eleven percent [11%] Capital
Percentage Interest and a one percent [1%] Profit Percentage Interest in each of
the Partnerships).

           "AMENDED AND RESTATED PARTNERSHIP AGREEMENTS" shall mean the amended
and restated limited partnership agreements of each of the Partnerships that
shall be executed by Prentiss and Brandywine OP upon the assignment by Knauer
and Gorman to Brandywine OP of

                                       2
<PAGE>

their respective 5.5% limited partnership interests in each of the Partnerships,
which Amended and Restated Partnership Agreements shall be generally in the form
of Exhibit G hereto.

           "APPLICABLE LAWS" shall mean any applicable building, zoning,
subdivision, environmental, health, safety or other governmental laws, statutes,
ordinances, resolutions, rules, codes, regulations, orders or determinations of
any Governmental Authority or of any insurance boards of underwriters (or other
body exercising similar functions), or any restrictive covenants or deed
restrictions affecting the Property or the ownership, operation, use,
maintenance or condition thereof.

           "ASSIGNED PARTNERSHIP INTERESTS" shall mean (a) a seventy-eight
percent (78%) Capital Percentage Interest (comprised of the entire one percent
(1%) Capital Percentage Interest owned by Prentiss as a general partner and a
seventy-seven percent (77%) Capital Percentage Interest owned by Prentiss as a
limited partner) and (b) a ninety-eight percent (98%) Profit Percentage Interest
(comprised of the entire one percent (1%) Profit Percentage Interest owned by
Prentiss as a general partner and a ninety-seven percent (97%) Profit Percentage
Interest owned by Prentiss as a limited partner), in each of the Partnerships.

           "ASSIGNMENT AND ASSUMPTION AGREEMENT" shall mean one or more
agreements whereby, subject to the allocation provisions in SECTION 7.8 hereof,
(a) Prentiss (1) assigns all of Prentiss' right, title and interest in and to
the Intangible Personal Property, to the extent assignable, and (2) indemnifies,
defends and holds Brandywine OP, the Partnerships and their respective agents,
employees, officers, partners, directors, shareholders and contractors harmless
with respect to all defaults, liabilities, claims, costs and expenses
(including, without limitation, reasonable attorneys' fees) relating to acts or
omissions accruing under the Assumed Operating Agreements before the Closing
Date; and (b) Brandywine OP indemnifies, defends and holds Prentiss harmless
with respect to all defaults, liabilities, claims, costs and expenses
(including, without limitation, reasonable attorneys' fees) relating to acts or
omissions accruing under the Assumed Operating Agreements after the Closing
Date.

           "ASSIGNMENT OF LEASES" shall mean the agreement whereby, subject to
the allocation provisions in SECTION 7.8 hereof, (a) Prentiss indemnifies,
defends and holds Brandywine OP, the Partnerships and their respective agents,
employees, officers, partners, directors, shareholders and contractors harmless
with respect to all defaults, liabilities, claims, costs and expenses
(including, without limitation, reasonable attorneys' fees) relating to acts or
omissions accruing under such Leases before the Closing Date; and (b) Brandywine
OP indemnifies, defends and holds Prentiss harmless with respect to all
defaults, liabilities, claims, costs and expenses (including, without
limitation, reasonable attorneys' fees) relating to acts or omissions accruing
under such Leases after the Closing Date.

           "ASSIGNMENT OF PARTNERSHIP INTERESTS" shall mean one or more
assignment and assumption agreements whereby (a) Prentiss assigns to Brandywine
OP (or its designee), all of Prentiss' right, title and interest in and to the
Assigned Partnership Interests free of liens and encumbrances, (b) Brandywine OP
assumes all of Prentiss' right, title and interests in and to the Assigned
Partnership Interests and indemnifies, defends and holds Prentiss and its
agents, employees, officers, directors and shareholders harmless with respect to
all defaults, liabilities, claims, costs and expenses (including, without
limitation, reasonable attorneys' fees) relating to

                                       3
<PAGE>

acts or omissions relating to the Assigned Partnership Interests or the
Partnerships after the Closing Date, and (c) Prentiss indemnifies, defends and
holds Brandywine OP and its agents, employees, officers, partners, directors and
shareholders harmless with respect to all defaults, liabilities, claims, costs
and expenses (including, without limitation, reasonable attorneys' fees)
relating to acts or omissions relating to the Assigned Partnership Interests or
the Partnerships accruing before the Closing Date.

           "ASSUMED OPERATING AGREEMENTS" shall mean the Operating Agreements
listed on SCHEDULE 3.7 hereto which are not to be terminated pursuant to the
last sentence of SECTION 3.7 hereof..

           "AUTHORIZATIONS" shall mean all licenses, permits and approvals
required by any governmental or quasi-governmental agency, body, department,
commission, board, bureau, instrumentality or officer, any owners association
created pursuant to deed restrictions affecting the Real Property or otherwise
appropriate with respect to the construction, ownership, operation, leasing,
maintenance, or use of the Property or any part thereof.

           "BRANDYWINE OP" shall mean Brandywine Operating Partnership, L.P., a
Delaware limited partnership.

           "BRANDYWINE OP'S OBJECTIONS" shall mean the objections defined as
such in SECTION 2.4(d) hereof.

           "BRANDYWINE OP'S ORGANIZATIONAL DOCUMENTS" shall mean the
organizational documents and all amendments thereto of Brandywine OP.

           "CAPITAL PERCENTAGE INTERESTS" shall have the meaning ascribed to
such term in the applicable Partnership Agreements.

           "CLOSING" shall mean the Closing of the purchase and sale of the
Assigned Partnership Interests and Purchased Stock pursuant to this Agreement
and shall be deemed to occur on the Closing Date.

           "CLOSING DATE" shall mean the date on which the Closing occurs.

           "CLOSING DOCUMENTS" shall mean the documents defined as such in
Section 7.1 hereof.

           "CORPORATIONS" shall mean Southpoint Inc. and Valleybrooke Inc.

           "DEPOSIT" shall mean all amounts deposited from time to time with
Escrow Agent by Brandywine OP pursuant to SECTION 2.3 hereof, plus all interest
or other earnings that may accrue thereon. All cash Deposits shall be invested
by Escrow Agent in a commercial bank or banks acceptable to Brandywine OP at
money market rates, or in such other investments as shall be approved in writing
by Prentiss and Brandywine OP. The Deposit shall be held and disbursed by Escrow
Agent in strict accordance with the terms and provisions of this Agreement.

                                       4
<PAGE>

           "ENVIRONMENTAL DAMAGES" shall mean all third-party claims, judgments,
damages, losses, penalties, fines, liabilities (including, without limitation,
punitive damages and strict liability), encumbrances, liens, costs and expenses
of investigation and defense of any claim, whether or not such is ultimately
defeated, and of any settlement or judgment, of whatever kind or nature,
contingent or otherwise, matured or unmatured, including, without limitation,
attorneys' fees and disbursements and consultants' fees, any of which arise as a
result of the existence of Hazardous Materials upon, about or beneath the
Property or migrating or threatening to migrate from the Property, or as a
result of the existence of a violation of Environmental Requirements pertaining
to the Property.

           "ENVIRONMENTAL REQUIREMENTS" shall mean (i) all applicable statutes,
regulations, rules, policies, ordinances, codes, licenses, permits, orders,
approvals, plans, authorizations, and similar items, of all Governmental
Authorities, and (ii) all judicial, administrative and regulatory decrees,
judgments and orders, in each case of (i) and (ii) relating to the protection of
human health or the environment from Hazardous Materials and health and safety
of employees or the public from Hazardous Materials, including, without
limitation, all requirements thereof pertaining to reporting, licensing,
permitting, investigation and remediation of emissions, discharges, releases or
threatened releases of Hazardous Materials into the air, surface water,
groundwater or land, or relating to the manufacture, processing, distribution,
use, treatment, storage, disposal, transport or handling of Hazardous Materials.

           "ESCROW AGENT" shall mean Chicago Title Insurance Company, whose
address is 2001 Bryan Street, Suite 1700, Dallas, Texas 75201, Attention: Ellen
Schwab.

           "EXISTING LIENS" shall mean the deed(s) of trust, mortgage(s),
assignments of leases, indemnities, loan agreements and other security
instruments securing, evidencing or executed in connection with the Existing
Notes described on EXHIBIT E hereto.

           "EXISTING NOTES" shall mean the promissory notes described on EXHIBIT
E hereto.

           "FIRPTA CERTIFICATES" shall mean the affidavit of Prentiss and PPL
under Section 1445 of the Internal Revenue Code, as amended, certifying that
neither Prentiss nor PPL is a foreign corporation, foreign partnership, foreign
trust, foreign estate or foreign person (as those terms are defined in the
Internal Revenue Code and regulations promulgated thereunder), in form and
substance satisfactory to Brandywine OP.

           "GORMAN" shall mean James J. Gorman, the holder of a 5.5% limited
partnership interest in each of the Partnerships.

           "GOVERNMENTAL AUTHORITY" shall mean any federal, state, county,
municipal or other government or any governmental or quasi-governmental agency,
department, commission, board, bureau, officer or instrumentality, foreign or
domestic, or any of them.

           "GROUND LEASE" shall mean each existing ground lease, and all
amendments thereto, under which Prentiss leases the Leasehold Estate Land, as
identified on EXHIBIT A-2 hereto.

                                       5
<PAGE>

           "GROUND LESSOR" shall mean each ground lessor under each Ground
Lease, which Ground Lessor shall mean and include each of Southpoint Inc. and
Valleybrooke Inc.

           "HAZARDOUS MATERIALS" shall mean any chemical substance: (i) which is
or becomes defined as a "HAZARDOUS SUBSTANCE," "HAZARDOUS WASTE," "HAZARDOUS
MATERIAL," "POLLUTANT," "CONTAMINANT," or "TOXIC," "EXPLOSIVE," "CORROSIVE,"
"FLAMMABLE," "INFECTIOUS," "RADIOACTIVE," "CARCINOGENIC," or "MUTAGENIC"
material under any law, regulation, rule, order, or other authority of the
federal, state or local governments, or any agency, department, commission,
board, or instrumentality thereof, regarding the protection of human health or
the environment from such chemical substances including, but not limited to, the
following federal laws and their amendments, analogous state and local laws, and
any regulations promulgated thereunder: the Clean Air Act, the Clean Water Act,
the Oil Pollution Control Act, the Comprehensive Environmental Response,
Compensation, and Liability Act of 1986, the Emergency Planning and Community
Right to Know Act, the Solid Waste Disposal Act, the Resource Conservation and
Recovery Act, the Safe Drinking Water Act, the Federal Insecticide, Fungicide
and Rodenticide Act, and the Toxic Substances Control Act, including, without
limitation, asbestos and gasoline and other petroleum products (including crude
oil or any fraction thereof); (ii) without limitation, which contains gasoline,
diesel fuel or other petroleum hydrocarbons; (iii) without limitation, which
contains asbestos-containing materials or urea formaldehyde foam insulation; or
(iv) without limitation, radon gas; provided, however, the term "HAZARDOUS
MATERIALS" shall not include de minimis quantities of substances of kinds and in
amounts ordinarily and customarily used or stored in properties similar to the
Property for the purposes of cleaning or other maintenance or operations and
otherwise in compliance with Environmental Requirements.

           "IMPROVEMENTS" shall mean all buildings, improvements, fixtures and
other items of real estate located on the various Parcels.

           "INSURANCE POLICIES" shall mean all policies of insurance maintained
by or on behalf of Prentiss, the Partnerships or the Corporations pertaining to
the Property, its operation, or any part thereof.

           "INTANGIBLE PERSONAL PROPERTY" shall mean all intangible personal
property owned or possessed by Prentiss, the Partnerships or the Corporations
and used in connection with the ownership, operation, leasing, occupancy or
maintenance of the Property, including, without limitation, (1) Prentiss', the
Partnerships' or the Corporations' exclusive right to use any trade names
associated with the Property and all variations thereof (other than variants of
Prentiss' legal name, all rights to which shall be retained by Prentiss), (2)
the Authorizations, (3) escrow accounts (subject to the provisions of Section
7.6 hereof), utility and development rights and privileges, general intangibles,
business records, plans and specifications pertaining to the Real Property and
the Personal Property, and (4) any unpaid award for taking by condemnation or
any damage to the Land by reason of a change of grade or location of or access
to any street or highway.

           "KNAUER" shall mean Christopher Knauer, the holder of a 5.5% limited
partnership interest in each of the Partnerships.

                                       6
<PAGE>

           "LAND" shall mean those certain parcels of real estate lying and
being in the Commonwealth of Pennsylvania, as more particularly described on
EXHIBIT A attached hereto, together with all easements, rights, privileges,
remainders, reversions and appurtenances thereunto belonging or in any way
appertaining, and all of the estate, right, title, interest, claim or demand
whatsoever of Prentiss, the Partnerships or the Corporations therein, in the
streets and ways adjacent thereto and in the beds thereof, either at law or in
equity, in possession or expectancy, now or hereafter acquired.

           "LEASED PROPERTY" shall mean all leased items of personal property.

           "LEASES" shall mean all leases, tenancies and other rights of
occupancy or use for any portion of the Real Property and leasehold estate,
together with any and all amendments thereto; provided, the Leases shall not
include any Ground Lease.

           "NOTE" shall mean a full recourse unsecured promissory note executed
by Brandywine OP, payable to Prentiss, bearing interest at the rate of 9.22% per
annum, payable interest only quarterly, with the first installment of interest
being payable on the first day of the calendar month that is three (3) full
calendar months following the Closing Date and continuing on the first day of
each quarter-annual anniversary of such date thereafter, and the entire
principal balance of and all accrued interest on the Note shall be due and
payable on the date that is three (3) years and one (1) day following the
Closing Date. The principal balance of the Note shall be equal to seventy-eight
percent (78%) of the amount by which the Purchase Price exceeds the outstanding
principal balance of the Existing Notes on the Closing Date.

           "OPERATING AGREEMENTS" shall mean all management, service, supply and
maintenance contracts, if any, in effect with respect to the Property and all
other contracts (other than the Leases) that affect the Property or are
otherwise related to the construction, ownership, operation, occupancy or
maintenance of the Property.

           "OWNER'S TITLE POLICY" shall mean an owner's policy of title
insurance for the Fee Estate Land and a leasehold policy of title insurance for
the Leasehold Estate Land issued to the Partnership by the Title Company,
pursuant to which the Title Company insures Brandywine OP's ownership of fee
simple title to the Fee Estate Land and leasehold title to the Leasehold Estate
Land subject only to Permitted Title Exceptions. The Owner's Title Policy shall
insure the Partnership in the aggregate amount of the Purchase Price and shall
be acceptable in form and substance to Brandywine OP. Brandywine OP may require
such deletions of standard exceptions and such title endorsements as are legally
available and customarily required by institutional investors purchasing
property comparable to the Property in each State where the Property is
situated. The description of the Land in the Owner's Title Policy shall be by
courses and distances or by reference to a legal, subdivided lot and shall be
identical to the description shown on the Survey.

           "PARCEL" shall mean each individual tract of the Land described on
EXHIBIT A hereto.

           "PARTNERSHIP AGREEMENTS" shall mean the limited partnership
agreements, as amended, creating the Partnerships.

                                       7
<PAGE>

           "PARTNERSHIPS" shall mean 111 Arrandale, 100 Arrandale, 440 Creamery
Way, 442 Creamery Way and 481 John Young.

           "PERMITTED TITLE EXCEPTIONS" shall mean the Existing Liens, Existing
Notes and those exceptions to title to the Real Property that are satisfactory
to Brandywine OP as determined pursuant to SECTION 2.4(d) hereof.

           "PERSONAL PROPERTY" shall mean collectively the Tangible Personal
Property and the Intangible Personal Property.

           "PRENTISS' ORGANIZATIONAL DOCUMENTS" shall mean the organizational
documents and all amendments thereto of Prentiss.

           "PROFIT PERCENTAGE INTEREST" shall have the meaning ascribed to such
term in the applicable Partnership Agreements.

           "PROPERTY" shall mean collectively the Real Property and the Personal
Property.

           "PURCHASED STOCK" shall mean seventy-eight (78) shares of common
stock in each of Southpoint Inc. and Valleybrooke Inc. to be sold by PPL to
Brandywine OP (or its designee) on the Closing Date.

           "PURCHASE PRICE" shall mean $20,104,512.00 payable in the manner
described in SECTION 2.2 hereof.

           "REAL PROPERTY" shall mean the Land and the Improvements.

           "RENT ROLL" shall have the meaning ascribed to such term in SECTION
2.4(b)(2) of this Agreement.

           "RETAINED INTERESTS" shall mean all right, title and interest to be
retained by Prentiss in each of the Partnerships other than the Assigned
Partnership Interests (which interest is comprised of an eleven percent [11%]
Capital Percentage Interest and a one percent [1%] Profit Percentage Interest)
and the eleven (11) shares of common stock to be retained by PPL in each of
Southpoint Inc. and Valleybrooke Inc.

           "STUDY PERIOD" shall mean the period commencing on the date this
Agreement has been fully executed and delivered by all parties hereto, and
continuing through February 16, 2001. Except as expressly noted herein to the
contrary, time periods herein referred to shall mean the time periods as in
effect, from time to time, at Dallas, Texas.

           "SUBMISSION MATTERS" shall mean all items Prentiss is required to
deliver to Prentiss pursuant to SECTION 2.4(b) hereof.

           "SURVEY" shall mean the survey defined as such in and prepared
pursuant to SECTION 2.4(d) hereof.

                                       8
<PAGE>

           "TANGIBLE PERSONAL PROPERTY" shall mean the items of tangible
personal property consisting of all furniture, fixtures, equipment, machinery
and other personal property of every kind and nature located on or used or
useful in the ownership and operation of the Property and owned by Prentiss, the
Partnerships or the Corporations, including, without limitation, Prentiss', the
Partnerships' or the Corporations' interest as lessee with respect to any such
Tangible Personal Property, other than (a) the items of personal property
identified on EXHIBIT D hereto, and (b) the Leased Property.

           "TITLE COMMITMENT" shall mean the title commitment and exception
documents defined as such in SECTION 2.4(d) hereof.

           "TITLE COMPANY" shall mean Fidelity National Title Insurance Company
or other title insurance underwriter selected by Brandywine OP.

           "UCC REPORTS" shall mean the reports defined as such in SECTION
2.4(d) hereof.

           "UTILITIES" shall mean public sanitary and storm sewers, natural gas
(if any), telephone, public water facilities, electrical facilities and all
other utility facilities and services (if any) necessary or appropriate for the
operation and occupancy of the Property as an office building.

           "WARRANTIES AND GUARANTIES" shall mean all warranties and guaranties
relating to the Improvements, or the Tangible Personal Property or any part
thereof.

                                  ARTICLE II.
             PURCHASE AND SALE; DEPOSIT; PAYMENT OF PURCHASE PRICE;
          STUDY PERIOD; ASSIGNMENTS SUBJECT TO EXISTING NOTES AND LIENS

     2.1   PURCHASE AND SALE. On the Closing Date, Prentiss agrees to sell the
Assigned Partnership Interests free and clear of all liens and encumbrances, PPL
agrees to sell the Purchased Stock free and clear of liens and encumbrances and
Brandywine OP agrees to purchase the Assigned Partnership Interests and
Purchased Stock in accordance with and subject to the other terms and conditions
set forth herein.

     2.2   PAYMENT OF PURCHASE PRICE; ASSIGNMENTS SUBJECT TO EXISTING NOTES AND
LIENS. The Purchase Price shall be paid to Prentiss and PPL in the following
manner:

           (a) Brandywine OP shall receive a credit against the Purchase Price
in an amount equal to the cash Deposit.

           (b) Brandywine OP shall acknowledge and agree that the Property is
subject to the unpaid balances of the Existing Notes payable to the lienholders
described in EXHIBIT E hereto having approximate unpaid principal balances in
the amounts specified in EXHIBIT E, and subject to the obligations contained in
the Existing Liens. Notwithstanding the foregoing, (i) to the extent that any of
the Existing Notes or Existing Liens (or the loan documents executed in
connection therewith) create personal liability for specified acts, omissions or
occurrences (such acts, omissions or occurrences being referred to as "CARVE-OUT
ACTIVITIES") and the associated personal liability being referred to as
"CARVE-OUT LIABILITY"), (A) Brandywine OP shall, if

                                       9
<PAGE>

Closing occurs, be responsible for any such Carve-Out Liability attributable to
Carve-Out Activities accruing and occurring from and after the Closing Date, and
shall and does hereby indemnify and hold Prentiss harmless with respect thereto,
and (B) Prentiss shall and does hereby indemnify and hold Brandywine OP harmless
with respect to Carve-Out Liability attributable to Carve-Out Activities
accruing or occurring prior to the Closing Date. If permitted by the holders of
the Existing Notes, Prentiss shall be released from all Carve-Out Liability
under the Existing Notes and Liens and Brandywine OP shall execute such
documents as the holders of the Existing Notes may require to evidence the
assumption by Brandywine OP of the Carve-Out Liability. If permitted by any
holder of an Existing Note, Prentiss shall be released from all Carve-Out
Liability under such Existing Note and Existing Liens securing payment of such
existing Note, and Brandywine OP shall execute such documents as the holder of
any such Existing Note may reasonably require to evidence the assumption by
Brandywine OP of the Carve-Out Liability attributable to Carve-Out Activities of
Brandywine OP or any of the Partnerships or Corporations accruing and occurring
from and after the Closing Date. The provisions of this SECTION 2.2(b) shall
survive the Closing.

           (c) Brandywine OP shall pay the amount by which the Purchase Price
exceeds the sum of (a) the cash Deposit, plus (b) the outstanding principal
balance of the Existing Notes on the Closing Date, as adjusted in the manner
specified in ARTICLE VII and as set forth below, to Prentiss at Closing by
executing and delivering the Note to Prentiss. Brandywine OP shall receive a
credit against the Purchase Price in an amount equal to the outstanding
principal balance of the Existing Notes on the Closing Date. The Purchase Price
shall be allocated among Assigned Partnership Interests and Purchased Stock in a
manner to be agreed upon by Prentiss, PPL and Brandywine OP on or before the
Closing Date.

     2.3   DEPOSIT. Within three (3) days after the execution hereof by both
Prentiss and Brandywine OP and as a condition precedent to the effectiveness of
this Agreement, Brandywine OP shall deliver to Escrow Agent a wire transfer or
check (a) in the sum of Fifty Dollars ($50.00) (the "INDEPENDENT
CONSIDERATION"), payable to the order of Prentiss representing the Independent
Consideration for Prentiss' execution of this Agreement (which check or the
proceeds of which wire transfer shall thereafter be delivered by Escrow Agent to
Prentiss), and (b) the sum of $100,000.00 (the proceeds of which wire transfer
or check Escrow Agent shall deposit and invest in an interest bearing account at
a financial institution acceptable to Brandywine OP or as otherwise agreed to in
writing by Prentiss and Brandywine OP). The proceeds of the wire transfer or
check are referred to herein as the "DEPOSIT" and Escrow Agent shall hold and
invest the Deposit pursuant to the terms, conditions and provisions of this
Agreement. All accrued interest on the Deposit shall become part of the Deposit.
The Deposit (regardless of whether it is the proceeds of a wire transfer or
check) shall be either (a) returned to Brandywine OP pursuant hereto, or (b)
paid to Prentiss pursuant hereto. For purposes of reporting earned interest with
respect to the Deposit, Prentiss' Federal Tax Identification Number is
75-2672997, and Brandywine OP's Federal Tax Identification Number is 23-2862640.

     2.4   STUDY PERIOD.

           (a) Brandywine OP and its agents, contractors and duly authorized
representatives shall have the right, until 5:00 p.m., Dallas, Texas time on the
last day of the Study Period, and thereafter unless, as provided below,
Brandywine OP notifies Prentiss in

                                       10
<PAGE>

writing prior to the expiration of the Study Period that Brandywine OP has
elected to terminate this Agreement, to enter upon the Real Property and to
perform, at Brandywine OP's expense, such economic, surveying, engineering,
topographic, environmental, marketing and other tests, studies and
investigations as Brandywine OP may deem appropriate. If such tests, studies and
investigations do not warrant, in Brandywine OP's sole, absolute and
unreviewable discretion, the acquisition of the Assigned Partnership Interests
and the Purchased Stock for the purposes contemplated by Brandywine OP, then
Brandywine OP may elect not to proceed with this transaction and shall notify
Prentiss and Escrow Agent, in writing prior to the expiration of the Study
Period, that Brandywine OP has elected to terminate this Agreement, in which
event this Agreement automatically shall terminate, the Deposit shall be
promptly returned to Brandywine OP and Brandywine OP, Prentiss and PPL shall be
released from all further liability or obligation hereunder except those which
expressly survive a termination of this Agreement. If Brandywine OP does not so
notify Prentiss of its determination to terminate this Agreement prior to the
expiration of the Study Period, then Brandywine OP shall be deemed to have
waived its right to terminate this Agreement pursuant to this SECTION 2.4.

           (b) Prentiss has delivered or made available at the Property the
following to Brandywine OP:

               (1)  Copies of all Leases in effect as of the date of this
           Agreement, together with, to the extent in Prentiss' possession or
           reasonably available to Prentiss, copies of all correspondence
           received from or sent to tenants of the Property.

               (2)  a Rent Roll (herein so called) certificate (with current
           rent roll and accounts receivable report attached) for the Property
           containing the following information with respect to each Lease: (i)
           a description of the space occupied thereby (including square feet,
           type of space, floor and tenant's pro rata share of common elements),
           (ii) tenant's name, (iii) the commencement date and expiration date
           thereof, (iv) the rental rate per square foot, (v) the amount of
           fixed monthly rental, (vi) the amount of any percentage or other
           additional rental and/or common area maintenance, tax, insurance and
           operating expenses and any other charges payable thereunder and, if
           applicable, the base year used in each Lease, (vii) the amount of any
           prepayment in rental, (viii) the amount of the security deposit or
           any other deposit thereunder, (ix) any free rent, concessions,
           rebates, refunds, refurbishment allowances or other inducements which
           any tenant will be entitled to receive after December 31, 2000
           (including, without limitation, any of the foregoing that may be
           payable in connection with renewals, extensions or expansions
           expressly contemplated in any of such Leases), (x) any options
           provided thereunder, including, without limitation, any renewal
           options, expansion options, purchase options and rights of first
           refusal and (xi) delinquency in rental or other charges set forth in
           the attached accounts receivable report.

               (3)  To the extent in Prentiss' possession or reasonably
           available to Prentiss, copies of all Authorizations including,
           without limitation, all certificates of occupancy, permits,
           authorizations, approvals (including drawings and enacting
           ordinances, if any), special exceptions, variances, and licenses
           issued by Governmental Authorities having jurisdiction over the
           Property and copies of all certificates issued by the local board of
           fire underwriters (or other body exercising similar functions)
           relating to

                                       11
<PAGE>

           the Property. For the purpose of this Agreement any Submission
           Matters in the possession of Prentiss or Prentiss' management company
           shall be deemed to be "reasonably available to Prentiss."

               (4)  To the extent in Prentiss' possession or reasonably
           available to Prentiss: (X) operating statements showing all income
           and expenses, profits and losses of the Property for the previous
           three (3) calendar years, which shall reflect (i) ad valorem taxes
           for the City, County and State or Commonwealth; (ii) expenses
           incurred for such period for water, electricity, natural gas and
           other utility charges; (iii) other operating expenses; (iv) total
           rents collected from tenants for such periods; and (v) other revenue
           collected and nature of such revenue; and (Y) financial statements
           for the Property for the previous three (3) calendar years,
           including, if available, the reports of accountants thereon.

               (5)  Operating and capital expenditure budgets for the current
           calendar year and, to the extent in Prentiss' possession or
           reasonably available to Prentiss, for the previous three (3) calendar
           years.

               (6)  All existing surveys and title policies for the Property
           that are reasonably available to Prentiss.

               (7)  A complete list of all Operating Agreements and leasing
           commission agreements relating to the Property in effect as of the
           date of this Agreement and complete copies of all such Operating
           Agreements and leasing commission agreements.

               (8)  A complete list of all Tangible Personal Property.

               (9)  To the extent in Prentiss' possession or reasonably
           available to Prentiss, any information in Prentiss' possession or
           reasonably available to Prentiss regarding current renditions or
           assessments on the Property or notices relative to change in
           valuation for ad valorem taxes.

               (10) A complete list of all Warranties and Guaranties in effect
           as of the date of this Agreement and complete copies of all such
           Warranties and Guaranties.

               (11) Copies of all soil tests, structural engineering tests,
           inspection reports, asbestos surveys, masonry tests, percolation
           tests, water, oil, gas, mineral, radon, formaldehyde, PCB or other
           environmental tests, audits or reports, market studies and site plans
           related to the Property in Prentiss' possession or reasonably
           available to Prentiss, together with copies of any and all
           correspondence, reports and other written documentation regarding the
           environmental aspects of the property or any toxic substances or
           equipment affecting or related to the Property.

               (12) If in Prentiss' possession or reasonably available to
           Prentiss, copies of complete sets of all architectural, mechanical,
           structural and/or electrical plans and specifications used in
           connection with the construction of or alterations or repairs to the
           Property.

                                       12
<PAGE>

               (13) If in Prentiss' possession or reasonably available to
           Prentiss, copies of as-built plans and specifications for the
           Property.

               (14) Parking, structural, mechanical or other engineering reports
           or studies related to the Property, if any, in Prentiss' possession
           or reasonably available to Prentiss.

               (15) To the extent in the possession of Prentiss or any affiliate
           of Prentiss or Prentiss' property manager, copies of credit reports
           and financial information on all tenants in possession of any of the
           Property and of any guarantors of such tenants' obligations.

               (16) Copies of all approvals from any owners associations having
           jurisdiction over the Real Property and copies of all correspondence
           from any such owners association.

               (17) Copies of the Existing Notes, Existing Liens and copies of
           any uncured notices of default or event of default from the holder(s)
           of the Existing Notes.

               (18) A copy of each Ground Lease, and all amendments thereto.

               (19) Copies of the Partnership Agreements and the organizational
           documents and minute books of each of Southpoint Inc. and
           Valleybrooke Inc., and financial statements and tax returns for each
           of the Partnerships, Southpoint Inc. and Valleybrooke Inc. for the
           years 1998, 1999 and 2000, to the extent reasonably available to
           Prentiss.

               (20) Copies of all Insurance Policies in effect, together with
           the name and telephone number of either a contact person at each
           insurance company or the insurance broker involved with the issuance
           of the Insurance Policies.

     Any reference to a document or information being in the possession of
Prentiss or similar phrase shall be construed to include documents or
information currently in the possession of any of the Partnerships or
Corporations.

     During the Study Period and thereafter until the Closing, Prentiss shall
make available to Brandywine OP, copies of all materials, correspondence, books,
records, financial statements, operating statements and any and all other
materials or information relating to the Partnerships, Southpoint Inc.,
Valleybrooke Inc. and the Property which come into Prentiss' possession or
control or are otherwise reasonably available to Prentiss from and after the
date on which the Submission Matters were delivered to Brandywine OP.

     Notwithstanding anything herein to the contrary, although Brandywine OP has
not received all of the deliveries described in this SECTION 2.4(b), Brandywine
OP has completed its feasibility study pursuant to SECTION 2.4(a) but reserves
the right to require, and Prentiss hereby agrees to deliver, to the extent
reasonably available to it, any item described in SECTION 2.4(b) not previously
delivered at any time during the period expiring six (6) months after the
Closing Date, which agreement shall survive the Closing Date for such six (6)
month period.

                                       13
<PAGE>

           (c) Brandywine OP shall indemnify and defend Prentiss against any
loss, damage or claim for personal injury or property damage (including
reasonable attorney's fees) arising from the entry upon the Property pursuant to
this Section 2.4 by Brandywine OP or any agents, contractors or employees of
Brandywine OP. Brandywine OP, at its own expense, shall restore any damage to
the Property caused by any of the tests or studies made by Brandywine OP. This
provision shall survive any termination of this Agreement and a closing of the
transaction contemplated hereby.

           (d) On or before 5:00 p.m. Dallas, Texas time on the date that is
five (5) days after the date of this Agreement, Prentiss shall deliver to
Brandywine OP, at Prentiss' sole cost and expense, the most recent Surveys of
the Land and the Improvements for all of the Land and Improvements which
constitute the Property, which are in the possession of Prentiss. Such Surveys
shall have been prepared by a Surveyor(s) licensed to practice in the State
where the Property is located. During the Study Period, Brandywine OP shall have
the right to update such Surveys, at Brandywine OP's sole cost. On or before the
Closing Date, Brandywine OP shall cause the Title Company to furnish to
Brandywine OP, at Prentiss' sole cost and expense, (i) a title insurance
commitment bearing an effective date subsequent to the date of this Agreement
issued by the Title Company covering the Real Property, binding the Title
Company to issue a ALTA Form Owner's Policy of Title Insurance, showing title to
be held currently by the Partnerships in a good, indefeasible and insurable
condition, together with legible copies of all documents identified in such
title insurance commitment as exceptions to title certified as true and complete
by the Title Company (collectively, the "TITLE COMMITMENT"), and (ii) reports of
searches of the Uniform Commercial Code records of both the county and State in
which the Property is located (collectively, the "UCC REPORTS") with respect to
the state of title to the Property. Prior to the expiration of the Study Period,
Brandywine OP shall notify Prentiss of any matters shown on the Survey or
identified in the Title Commitment or the UCC Reports that Brandywine OP is
unwilling to accept (collectively, "BRANDYWINE OP'S OBJECTIONS"); however,
Brandywine OP may not object to any Ground Lease, the Existing Notes and
Existing Liens. If any of Brandywine OP's Objections consist of delinquent
taxes, mortgages, deeds of trust, security agreements, construction or
mechanics' liens, tax liens or other liens or charges in a fixed sum or capable
of computation as a fixed sum, then, to that extent, notwithstanding anything
herein to the contrary, Prentiss shall be obligated to pay and discharge (or
bond against in a manner sufficient to cause the Title Company to insure over
such Brandywine OP's Objections) any such Brandywine OP's Objections and Escrow
Agent is authorized to pay and discharge at Closing such Brandywine OP's
Objections to the extent not paid and discharged or bonded against at Closing.
Prentiss shall not be obligated to incur any expenses to cure any non-monetary
Brandywine OP's Objections (including, without limitation, any lis pendens filed
against the Property) unless Prentiss agrees to cure such non-monetary
Brandywine OP's Objections as hereinafter provided. Prentiss shall notify
Brandywine OP on or before the Closing Date whether Prentiss agrees to cure such
non-monetary Brandywine OP's Objections. If Prentiss notifies Brandywine OP in
writing on or before the Closing Date that Prentiss agrees to cure such
non-monetary Brandywine OP's Objections, Prentiss shall correct such
non-monetary Brandywine OP's Objections on or before the Closing Date to the
reasonable satisfaction of Brandywine OP. If Prentiss does not notify Brandywine
OP on or before the Closing Date of its agreement to cure such non-monetary
Brandywine OP's Objections, Prentiss shall be deemed to have elected not to cure
such non-monetary Brandywine OP's Objections, and Brandywine OP shall elect (1)
to waive such non-monetary Brandywine OP's Objections or

                                       14
<PAGE>

(2) to terminate this Agreement, in which case the Deposit shall be promptly
returned to Brandywine OP and the parties hereto shall be released from all
further obligations hereunder except those which expressly survive a termination
of this Agreement. Prentiss shall not, after the date of this Agreement, permit
the Partnerships to subject the Real Property to or permit or suffer to exist
any liens, encumbrances, covenants, conditions, restrictions, easements or other
title matters or seek any zoning changes or take any other action which may
affect or modify the status of title without Brandywine OP's prior written
consent. The Existing Notes, Existing Liens, each Ground Lease and all title
matters revealed by the Title Commitment, UCC Reports and Survey and not
objected to by Brandywine OP as provided above (other than those rendering title
defeasible and delinquent taxes, mortgages, deeds of trust, security agreements
and other liens and charges that are to be paid at Closing or bonded against as
provided above) shall be deemed Permitted Title Exceptions. Notwithstanding the
foregoing, Brandywine OP shall not be required to close the transactions
described in this Agreement if title to the Real Property on the Closing Date is
subject to any matters which (i) may arise subsequent to the effective date of
the Title Commitment, UCC Reports and Survey examined by Brandywine OP during
the Study Period and (ii) impairs title to any portion of the Property and will
not be released or bonded against on or before the Closing Date. If a title
exception is disclosed by the Title Company which was not shown in the Title
Commitment or Survey and was not the result of any of the Partnerships' acts or
omissions, then, unless Prentiss notifies Brandywine OP in writing by the
Closing Date that Prentiss agrees to take such action as may be necessary to
release such title exception on or before the Closing Date, Brandywine OP may
(i) terminate this Agreement by written notice to Prentiss, in which event the
Deposit shall be promptly returned to Brandywine OP and the parties hereto shall
be released from all further obligations hereunder except those which expressly
survive a termination of this Agreement, or (ii) waive its objections to such
title exception and consummate the transactions contemplated herein.

                                  ARTICLE III.
                    PRENTISS' REPRESENTATIONS AND WARRANTIES

     To induce Brandywine OP to enter into this Agreement and to acquire the
Assigned Partnership Interests, Prentiss makes the following representations and
warranties with respect to the Property, the Partnerships and the Corporations,
as applicable, upon each of which Prentiss acknowledges and agrees that
Brandywine OP is entitled to rely and has relied:

     3.1   ORGANIZATION AND POWER. Prentiss is a limited partnership duly
formed, validly existing and in good standing under the laws of the State of
Delaware, is duly qualified to transact business in the Commonwealth of
Pennsylvania and State of Delaware, and has all requisite powers and all
material governmental licenses, authorizations, consents and approvals to carry
on its business as now conducted and to enter into and perform its obligations
hereunder and under any document or instrument required to be executed and
delivered on behalf of Prentiss hereunder. PPL is a corporation duly formed,
validly existing and in good standing under the laws of the State of Delaware,
and has all requisite powers and all material governmental licenses,
authorizations, consents and approvals to carry on its business as now conducted
and to enter into and perform its obligations hereunder and under any document
or instrument required to be executed and delivered on behalf of PPL hereunder.

                                       15
<PAGE>

     3.2   AUTHORIZATION, EXECUTION AND DISCLOSURE. This Agreement has been duly
authorized by all necessary action on the part of Prentiss and PPL, has been
duly executed and delivered by Prentiss and PPL, constitutes the valid and
binding agreement of Prentiss and PPL and is enforceable in accordance with its
terms, subject to the effect of applicable bankruptcy, insolvency,
reorganization, arrangement, moratorium or other similar laws affecting the
rights of creditors generally. Except for the consents of the holders of the
Existing Notes, there is no other person or entity who has an ownership interest
in the Property, the Partnerships or the Corporations or whose consent is
required in connection with Prentiss' or PPL's performance of its obligations
hereunder which has not been obtained. The person executing this Agreement on
behalf of Prentiss and PPL has the authority to do so. Neither Prentiss nor PPL
has or will intentionally conceal any information regarding the Partnerships,
the Corporations or the Property.

     3.3   NON-CONTRAVENTION. The execution and delivery of, and the performance
by Prentiss of its obligations under, this Agreement do not and will not (a)
contravene, or constitute a default under, any provision of (i) Prentiss'
Organizational Documents, the articles of incorporations and bylaws of PPL, the
articles of incorporation and bylaws of the Corporations, or any of the
Partnership Agreements, (ii) applicable law or regulation or any agreement,
judgment, injunction, order, decree or other instrument binding upon Prentiss or
to which the Property is subject, the result of which could have a material
adverse effect on either the value of the Property or Prentiss' ability to
assign the Assigned Partnership Interests to Brandywine OP (or its designee)
and/or Prentiss' ability to perform its obligations under this Agreement, or
PPL's ability to transfer the Purchased Stock to Brandywine OP (or its designee)
and or PPL's ability to perform its obligations under this Agreement, or (iii)
result in the creation of any lien or other encumbrance on any asset of
Prentiss, PPL, any of the Partnerships or the Corporations. There are no
outstanding agreements (written or oral) pursuant to which Prentiss, any of the
Partnerships or the Corporations (or any predecessor to or representative of
Prentiss) has agreed to sell or has granted an option or right of first refusal
to purchase the Property or any part thereof.

     3.4   NO SPECIAL TAXES. Prentiss has no knowledge of, nor has it received
any notice of, any special taxes or assessments relating to the Property or any
part thereof or any planned public improvements that may result in a special tax
or assessment against the Property.

     3.5   COMPLIANCE WITH EXISTING LAWS AND RESTRICTIVE COVENANTS. To Prentiss'
knowledge, each of the Partnerships possesses all Authorizations, each of which
is valid and in full force and effect, and no provision, condition or limitation
of any of the Authorizations has been breached or violated. Neither Prentiss,
nor, to Prentiss' knowledge, either any of the Partnerships or the Corporations,
has received any notice within the past three years, of any existing or
threatened violation of any provision of any (a) Applicable Laws including, but
not limited to, those of environmental agencies or insurance boards of
underwriters with respect to the ownership, operation, use, maintenance or
condition of the Property or any part thereof, or requiring any repairs or
alterations to the Property other than those that have been made prior to the
date hereof, and (b) restrictive covenants or deed restrictions affecting the
Real Property.

     3.6   PERSONAL PROPERTY. Except for the Existing Liens, all of the Personal
Property owned by the Partnerships is free and clear of all liens and
encumbrances except for those which

                                       16
<PAGE>

will be discharged by Prentiss at Closing, and each of the Partnerships has good
and merchantable title thereto.

     3.7   OPERATING AGREEMENTS. There are no management, service, supply,
maintenance, employment or other contracts in effect with respect to the
Property, the Partnerships or the Corporations of any nature whatsoever, written
or oral, other than the Assumed Operating Agreements and the Operating
Agreements to be terminated pursuant to the last sentence of this SECTION 3.7.
To Prentiss' knowledge, each of the Partnerships and each of the Corporations
has performed all of its respective obligations under each of the Assumed
Operating Agreements in all material respects and no fact or circumstance has
occurred which, by itself or with the passage of time or the giving of notice or
both, would constitute a default under any of the Assumed Operating Agreements.
To Prentiss' knowledge, all other parties to the Assumed Operating Agreements
have performed all of their obligations thereunder in all material respects, and
are not in default thereunder in any material respect. Neither Prentiss, the
Partnerships nor the Corporations has received any notice of any intention by
any of the parties to any of the Assumed Operating Agreements to cancel the
same, nor has Prentiss, the Partnerships or the Corporations canceled any of
same. At the written request or Brandywine OP, Prentiss shall cause any
Operating Agreements designated by Brandywine OP which are terminable without
penalty to be terminated as of the Closing Date.

     3.8   CONDEMNATION PROCEEDINGS; ROADWAYS. Prentiss has received no notice
of any condemnation or eminent domain proceeding pending or, to Prentiss'
knowledge, no such action is threatened, against the Property or any part
thereof. Prentiss has no knowledge of any change or proposed change in the
route, grade or width of, or otherwise affecting, any street, creek or road
adjacent to or serving the Real Property.

     3.9   ACTIONS OR PROCEEDINGS. There is no action, suit or proceeding
pending or known to Prentiss to be threatened against or affecting Prentiss, any
of the Partnerships or the Corporations in any court, before any arbitrator or
before or by any Governmental Authority which (a) in any manner raises any
question affecting the validity or enforceability of this Agreement or any other
agreement or instrument to which Prentiss or any of the Partnerships or any of
the Corporations is a party or by which it is bound and that is or is to be used
in connection with, or is contemplated by, this Agreement, (b) is reasonably
likely to materially and adversely affect the business, financial position or
results of operations of Prentiss, any of the Partnerships, any of the
Corporations or the Property, (c) is reasonably likely to materially and
adversely affect the ability of Prentiss to perform its obligations hereunder,
or under any document to be delivered pursuant hereto, or the ability of the
Partnerships or the Corporations to own and operate their respective Property,
(d) is reasonably likely to create a lien on the Property, any part thereof or
any interest therein or (e) is reasonably likely to otherwise materially and
adversely affect any of the Partnerships, the Corporations or the Property, any
part thereof or any interest therein or the use, operation, condition or
occupancy thereof.

     3.10  BANKRUPTCY. No Act of Bankruptcy has occurred with respect to
Prentiss, any of the Partnerships or the Corporations.

     3.11  HAZARDOUS SUBSTANCES. To Prentiss' knowledge, neither any of the
Partnerships. the Corporations nor any previous owner, tenant, occupant or user
of the Property, nor any other

                                       17
<PAGE>

person, has engaged in or permitted any operations or activities upon, or any
use or occupancy of the Property or any portion thereof, for the purpose of or
in any way involving the handling, manufacture, treatment, storage, use,
generation, release, discharge, refining, dumping or disposal of any Hazardous
Materials on, under, in or about the Property in violation of any Applicable
Laws. To Prentiss' knowledge, no Hazardous Materials have migrated from or to
the Property upon, about, or beneath other properties in violation of any
Environmental Requirements. To Prentiss' knowledge, neither the Property nor its
existing or prior uses fail or failed to materially comply with Environmental
Requirements. Prentiss has no knowledge of any permits, licenses or other
authorizations which are required under any Environmental Requirements with
regard to the current uses of the Property which have not been obtained and
complied with. To Prentiss' knowledge, neither any of the Partnerships, the
Corporations nor any prior owner, occupant or user of the Property has received
any written notice concerning any alleged violation of Environmental
Requirements in connection with the Property or any liability for Environmental
Damages in connection with the Property for which any of the Partnerships or the
Corporations (or Brandywine OP after Closing) may be liable. To Prentiss'
knowledge, no Hazardous Materials are constructed, deposited, stored or
otherwise located on, under, in or about the Property in violation of any
Environmental Requirements. To Prentiss' knowledge, there exists no writ,
injunction, decree, order or judgment outstanding, nor any lawsuit, claim,
proceeding, citation, summons or investigation, pending or threatened, relating
to any alleged violation of Environmental Requirements on the Property, or from
the suspected presence of Hazardous Materials thereon, or relating to any
Environmental Damages. To Prentiss' knowledge, there are no underground or above
ground chemical treatment or storage tanks, or gas or oil wells are located on
the Property. The representations and warranties made by Prentiss in this
SECTION 3.11 shall be subject to the matters disclosed in the environmental
reports delivered by Prentiss to Brandywine OP pursuant to SECTION 2.4(b)(12)
hereof.

     3.12  PARTIES IN POSSESSION. There are no parties in possession of the
Property except for tenants under written leases, copies of which will be
delivered to Brandywine OP pursuant to the terms hereof.

     3.13  LEASES. There are no leases, concessions or occupancy agreements in
effect with respect to the Real Property other than the Leases listed on the
Rent Roll attached as SCHEDULE 3.13; and SCHEDULE 3.13 attached hereto is a
complete and correct list of all Leases in effect on the date of this Agreement.
Neither Prentiss nor the Partnerships has sent out any written notice of any
default to any tenant under any Lease which has not been cured, except as set
forth on SCHEDULE 3.13. To Prentiss' knowledge, each of the Partnerships has
performed all obligations required of it under all of the Leases and there
remain no unfulfilled obligations of any of the Partnerships under the Leases,
the nonperformance of which could entitle a tenant to damages under such Lease
or could cause any of the Partnerships to be in default under such Lease. Except
as shown on SCHEDULE 3.13, no tenant has given written notice to any of the
Partnerships of its intention to institute litigation with respect to any Lease
that has not been dismissed, and Prentiss has not been served with a citation
notifying any of the Partnerships of any litigation with respect to any Lease
that has not been dismissed. None of the Leases and none of the rents or other
amounts payable thereunder have been assigned, pledged or encumbered except for
(a) any assignments, pledges or encumbrances which will be fully released on or
before the Closing Date, and (b) the Existing Liens. The Rent Roll is true,
correct and complete in all material respects as of the date shown in the Rent
Roll and, to Prentiss'

                                       18
<PAGE>

knowledge, there has been no material adverse change with respect to any of the
items shown on the Rent Roll during the period from the date thereof to the date
of this Agreement, except as shown thereon.

     3.14  LEASED PROPERTY. To Prentiss' knowledge, all leases of the Leased
Property, if any, are in good standing and free from default.

     3.15  NO UNPAID CHARGES; FINANCIAL STATEMENTS. Subject to SECTION 7.8
hereof, there are no unpaid charges, debts, liabilities, claims or obligations
arising from the construction, occupancy, ownership, use or operation of the
Property which could give rise to any mechanic's or materialmen's or other
statutory lien against the Property, or any part thereof, or for which
Brandywine OP will be responsible or which will be due upon the initial
occupancy of vacant space (such as water or sewer connection or tap-in fee). The
financial statements and tax returns of the Partnerships and the Corporations
delivered pursuant to SECTION 2.4(b)(20) were true, correct and complete in all
material respects as of the respective dates thereof.

     3.16  CONDITION OF IMPROVEMENTS. Neither Prentiss, any of the Partnerships
nor any of the Corporations has received any written notice, from any third
party alleging that (a) any of the Improvements (i) are defective in design or
construction, (ii) are not in operating condition and a satisfactory state of
repair, or (iii) have roof leaks, (b) any mechanical systems are not in
reasonable working order and repair, or (c) any of the Partnerships or
Corporations has failed to operate the Property in a commercially reasonable
manner consistent with a modern office building; provided, however, the
foregoing representation and warranty as to notices received shall not include
any representation or warranty as to notices concerning the aesthetic or other
subjective quality of the design of the Property or any system, element or
component thereof and no representation or warranty shall be deemed made as to
any defect disclosed in any property condition report obtained by Brandywine OP
in connection with the Property.

     3.17  ACCESS. Prentiss has no knowledge of any pending or threatened
governmental proceeding or any other fact or condition which would limit or
result in the termination of the Property's existing access to and from public
streets or roads.

     3.18  NO COMMITMENTS. No commitments have been made to any Governmental
Authority, utility company, school board, church or other religious body, or any
homeowners' association or any other organization, group or individual, relating
to the Property which would impose an obligation upon Brandywine OP, any of the
Partnerships or the Corporations to make any contribution or dedication of money
or land or to construct, install or maintain any improvements of a public or
private nature on or off the Property. Without limiting the generality of the
foregoing, none of the Partnerships is a party to any paving agreements or
undertakings, payback agreements, revenue bonds, utility debt service expenses
or other charges or expenses upon or relating to any of the Property or
applicable thereto.

     3.19  NONE OF THE PARTNERSHIPS NOR PRENTISS IS A "FOREIGN PERSON". None of
the Partnerships nor Prentiss is a "FOREIGN PERSON" within the meaning of
Section 1445 of the Internal Revenue Code, as amended (i.e., neither the
Partnerships nor Prentiss is a foreign corporation, foreign partnership, foreign
trust, foreign estate or foreign person as those terms are defined in the
Internal Revenue Code and regulations promulgated thereunder).

                                       19
<PAGE>

     3.20  LEASING COMMISSIONS. No brokerage or leasing commissions or other
fees or compensation are due or payable, or which will become due and payable as
a result of agreements in place, to any person, firm, corporation or other
entity with respect to or on account of any of the Leases or any extension or
renewals thereof, except as set forth on SCHEDULE 3.20 OR 6.4(g) hereof.

     3.21  OTHER AGREEMENTS. There are no options, contracts or other
obligations outstanding for the sale, exchange or transfer of any of the
Property or any interest therein which would be superior to the rights of
Brandywine OP under this Agreement or which would survive Closing, other than
buy/sell provisions in the Partnership Agreements.

     3.22  EXISTING SECURED INDEBTEDNESS. There is no debt secured by liens on
the Real Property, or any portion thereof, which will not be released and
discharged as of the Closing, other than the Existing Notes and the Existing
Liens. None of the Partnerships is in default under the Existing Notes or the
Existing Liens, to Prentiss' knowledge, no event has occurred which, with the
passage of time or the giving of notice, or both, would constitute a default
thereunder, and EXHIBIT E is true, accurate and complete in all material
respects.

     3.23  EMPLOYMENT ON "AT-WILL" BASIS. All persons and entities presently
employed in connection with the operation and maintenance of the Property are
employed on an "AT WILL" basis, are dischargeable upon thirty (30) days' notice
and, unless otherwise directed by Brandywine OP, shall be terminated by Prentiss
as of Closing. There are no labor disputes pending, nor to the best of Prentiss'
knowledge, contemplated pertaining to the operation or maintenance of the
Property, or any part thereof. Neither Prentiss, any of the Partnerships nor the
Corporations has any employment agreements, either written or oral, with any
person which would require Brandywine OP to employ any person after the date
hereof or the Closing Date.

     3.24  ADDITIONAL REPRESENTATIONS AND WARRANTIES WITH RESPECT TO THE
PARTNERSHIPS.

           (a) Each of the Partnerships is a limited partnership duly organized
and validly existing under the laws of the Commonwealth of Pennsylvania, and
each of the Partnerships is in good standing in such state;

           (b) The Partnership Agreements delivered pursuant to SECTION
2.4(b)(20) are true and correct copies of the agreements of limited partnership
of the Partnerships, as amended through the date hereof. The Partnership
Agreements list all existing Partners (individually, a "PARTNER" and
collectively, the "PARTNERS") of the Partnership; and the Partnership Agreements
accurately list the percentage ownership interests of Prentiss in each of the
Partnerships; however, in making the foregoing representation and warranty,
Prentiss has assumed that neither Gorman nor Knauer has assigned or encumbered
any of their respective partnership interests in the Partnerships. Prentiss is
the sole owner of the partnership interests shown on such books and in the
Partnership Agreements as being owned by Prentiss, free and clear of all liens
and encumbrances. The partnership interests issued by the Partnerships have been
issued in compliance with the Partnership Agreements, and such interests were
not issued in violation of any federal or state securities laws;

                                       20
<PAGE>

           (c) As of the date hereof, the capital account of each of the
Partners in the Partnerships is as set forth on EXHIBIT H and none of the
Partners has been asked to make a capital contribution to any of the
Partnerships other than capital contributions that have been made in full as of
the date hereof;

           (d) There are no equity, revenue, cash flow, profit or other
participations or similar rights which apply to the Partnerships except as set
forth in the Partnership Agreements;

           (e) Except as provided in the Partnership Agreements, there are no
rights, subscriptions, options, rights of first refusal, conversion rights or
other agreements to purchase or to otherwise acquire any securities or
obligations of any kind convertible into any partnership interest or other
equity interests or participation interests in any Partnerships except for those
rights created by the put/call agreements to be assigned by Prentiss pursuant to
the Assignment of Put/Call Agreements; and

           (f) None of the Partnerships has engaged in any business other than
the ownership, development, leasing and management of the Property, and none of
the Partnerships has any subsidiaries or has ever owned stock, shares or
interests of any kind whatsoever in any entity.

           (g) Prentiss shall cause each of the Partnerships to make the
election provided under Section 754 of the Internal Revenue Code of 1986, as
amended, if requested by Brandywine OP or its designee at any time after the
Closing Date. Brandywine OP may make such request for one or more of the
Partnerships without being required to make such request for all of the
Partnerships.

     3.25  REPRESENTATIONS AND WARRANTIES OF PPL. To induce Brandywine OP to
induce to enter into this Agreement and to acquire the Purchased Stock, PPL and
Prentiss make the following representations and warranties, jointly and
severally, with respect to the Ground Lease, Valleybrooke Inc. and Southpoint
Inc., upon each of which PPL and Prentiss acknowledge and agree that Brandywine
OP is entitled to rely and has relied:

           (a) Each of Southpoint Inc. and Valleybrooke Inc. is duly organized,
validly existing and in good standing under the laws of the Commonwealth of
Pennsylvania;

           (b) The authorized equity securities of each of Southpoint Inc. and
Valleybrooke Inc. consist solely of 1,000 shares of each such corporation, of
which 100 shares are issued and outstanding for each such corporation (the
"OUTSTANDING SHARES"). The Outstanding Shares are duly authorized, validly
issued, fully paid and nonassessable. PPL is the record and beneficial owner of,
and has good title to, eighty-nine (89) shares of each of Southpoint Inc. and
Valleybrooke Inc., free and clear of all liens, claims, security interests,
assignments, options, voting trusts, proxies, voting agreements, understandings
or arrangements with respect to voting, and adverse claims to title of any kind
or character. Except for the Option Agreement, there are no outstanding
subscriptions, options, warrants, calls or rights of any kind relating to or
providing for the issuance, sale, delivery or transfer of securities of any
class of either Southpoint Inc. or Valleybrooke Inc.;

                                       21
<PAGE>

           (c) Except for the liabilities or obligations shown in the financial
statements of Southpoint Inc. and Valleybrooke Inc. delivered pursuant to
SECTION 2.4(b)(20) hereof, neither of such corporations has any liabilities or
obligations, other than liabilities accrued and discharged in such Corporations'
ordinary course of business. The financial statements and tax returns of
Southpoint Inc. and Valleybrooke Inc. delivered pursuant to SECTION 2.4(b)(20)
were true, correct and complete in all material respects as of the respective
dates thereof;

           (d) Neither Southpoint Inc. nor Valleybrooke Inc. is a "FOREIGN
PERSON" within the meaning of Section 1445 of the Internal Revenue Code, as
amended;

           (e) Neither Southpoint Inc. nor Valleybrooke Inc. has engaged in any
business or activities other than the business of owning the real property
described in each Ground Lease;

           (f) The articles of incorporation, bylaws and minute books of each of
Southpoint Inc. and Valleybrooke Inc. delivered pursuant to SECTION 2.4(b)(20)
hereof are true and complete copies thereof; and

           (g) Each Ground Lease is valid and in full force and effect. No
Ground Lessor is in default under any Ground Lease; to PPL's knowledge, no event
has occurred which, with the passage of time or the giving of notice, or both,
would constitute a default under any Ground Lease; and EXHIBIT B is a true,
accurate and complete description, in all material respects, of each Ground
Lease and all amendments thereto.

     3.26  LIMITATIONS ON REPRESENTATIONS AND WARRANTIES. BRANDYWINE OP HEREBY
AGREES AND ACKNOWLEDGES THAT, EXCEPT AS SET FORTH IN THIS ARTICLE III, OR AS
OTHERWISE EXPRESSLY STATED HEREIN OR IN ANY DOCUMENTS EXECUTED IN CONNECTION
HEREWITH, NEITHER PRENTISS, PPL NOR ANY AGENT, ATTORNEY, EMPLOYEE OR
REPRESENTATIVE OF PRENTISS OR PPL HAS MADE ANY REPRESENTATION WHATSOEVER
REGARDING THE SUBJECT MATTER OF THIS AGREEMENT, OR ANY PART THEREOF, INCLUDING
(WITHOUT LIMITING THE GENERALITY OF THE FOREGOING) REPRESENTATIONS OR WARRANTIES
AS TO THE PHYSICAL NATURE OR CONDITION OF THE PROPERTY OR THE CAPABILITIES
THEREOF, AND THAT BRANDYWINE OP, IN EXECUTING, DELIVERING AND/OR PERFORMING THIS
AGREEMENT, DOES NOT RELY UPON ANY STATEMENT AND/OR INFORMATION TO WHOMEVER MADE
OR GIVEN, DIRECTLY OR INDIRECTLY, ORALLY OR IN WRITING, BY ANY INDIVIDUAL, FIRM
OR CORPORATION EXCEPT THOSE EXPRESSLY CONTAINED HEREIN OR DELIVERED PURSUANT
THERETO OR IN ANY DOCUMENTS EXECUTED IN CONNECTION HEREWITH. EXCEPT AS OTHERWISE
PROVIDED HEREIN, BRANDYWINE OP AGREES TO TAKE THE ASSIGNED PARTNERSHIP INTERESTS
AND PURCHASED STOCK "AS IS," AS OF THE DATE HEREOF AND INDIRECT INTERESTS IN THE
PROPERTY. IN ADDITION, EXCEPT AS SET FORTH HEREIN, PRENTISS MAKES NO
REPRESENTATIONS OR WARRANTIES REGARDING THE COMPLIANCE WITH ANY ENVIRONMENTAL
REQUIREMENTS, INCLUDING THE EXISTENCE IN OR ON THE PROPERTY OF HAZARDOUS
MATERIALS. THE PROVISIONS OF THIS PARAGRAPH SHALL SURVIVE THE CLOSING OR ANY
TERMINATION HEREOF.

                                       22
<PAGE>

Each of the representations and warranties contained in this ARTICLE III and its
various subparagraphs are intended for the benefit of Brandywine OP and may be
waived in whole or in part by Brandywine OP. All rights and remedies arising in
connection with the untruth or inaccuracy of any such representations and
warranties shall survive the Closing of the transaction contemplated hereby as
provided in SECTION 10.11 hereof, except to the extent that Prentiss gives
Brandywine OP written notice prior to Closing of the untruth or inaccuracy of
any representation or warranty, Brandywine OP otherwise obtains actual knowledge
prior to Closing of the untruth or inaccuracy of any representation or warranty,
and Brandywine OP nevertheless elects to close this transaction. Brandywine OP
shall be deemed to have actual knowledge of the untruth or inaccuracy of any
representation or warranty only if (i) Brandywine OP receives written notice
from Prentiss satisfying the foregoing requirements, or (ii) Gerard H. Sweeney,
George Hasenecz, Michael Diliberto, Suzanne Stumpf or Brad A. Molotsky has
actual knowledge of any such untruth or inaccuracy. Except to the extent
otherwise expressly provided in the immediately preceding sentence, no
investigation, audit, inspection, review or the like conducted by or on behalf
of Brandywine OP shall be deemed to terminate the effect of any such
representations, warranties and covenants, it being understood that Brandywine
OP has the right to rely thereon and that each such representation and warranty
constitutes a material inducement to Brandywine OP to execute this Agreement and
to close the transaction contemplated hereby and to pay the Purchase Price to
Prentiss.

If any of Prentiss' or PPL's representations and warranties made hereunder are
found by Brandywine OP to be incorrect prior to Closing to the extent they
affect the Property or its operation in any material respect or any of the
subject matter thereof, or the ownership of the Assigned Partnership Interests
or the Purchased Stock, Brandywine OP shall inform Prentiss in writing and
Brandywine OP's sole remedy, except as otherwise expressly provided in CLAUSE
(a)(ii) of the first sentence of SECTION 9.3 hereof or the last sentence of
SECTION 9.3 hereof, shall be termination of this Agreement on account thereof
and refund of the Deposit. If Brandywine OP elects not to so terminate this
Agreement, any remedy of Brandywine OP for breach of such warranties and
representations made prior to the Closing shall be deemed to be irrevocably
waived. Notwithstanding anything to the contrary contained in this Article, if
Prentiss or PPL breaches any representation or warranty made by Prentiss or PPL
and if prior to Closing Brandywine OP notifies Prentiss or PPL that it elects to
terminate this Agreement on account of such breach, Prentiss may by written
notice to Brandywine OP given or before the Closing Date agree to cure the
breach (which breach must be cured on or before the Closing Date), and
Brandywine OP shall thereupon be obligated to close the transaction and accept
such cure as Brandywine OP's sole remedy for such breach.

The term "TO PRENTISS' KNOWLEDGE" or similar phrase shall mean the knowledge of
Prentiss' chief executive officer, general counsel, chief financial officer,
Hank Gulbrandsen, Peter Hausmann and the current building engineer, property
manager and leasing agent (collectively, "PRENTISS' PERSONNEL WITH KNOWLEDGE")
for the Property and such inquiry shall include the direction by Prentiss to
such persons to review all files in their possession relating to the operation,
ownership, maintenance and management of the Property. Prentiss covenants that
if prior to Closing Prentiss obtains actual knowledge that any of the facts
represented and warranted by Prentiss under this Agreement are or become untrue
or inaccurate in any material respect, it will promptly inform Brandywine OP in
writing of its discovery.

                                       23
<PAGE>

Prentiss' Personnel with Knowledge shall not have any personal liability under
this Agreement in their respective capacities as officers and/or directors of
Prentiss.

                                  ARTICLE IV.
                 BRANDYWINE OP'S REPRESENTATIONS AND WARRANTIES

     To induce Prentiss and PPL to enter into this Agreement and to assign the
Assigned Partnership Interests and Purchased Stock, Brandywine OP hereby makes
the following representations and warranties, upon each of which Brandywine OP
acknowledges and agrees that Prentiss and PPL is entitled to rely and has
relied:

     4.1   ORGANIZATION AND POWER. Brandywine OP is a limited partnership, duly
formed, validly existing and in good standing under the laws of the State of
Delaware, and has all requisite partnership powers and all material governmental
licenses, authorizations, consents and approvals required to carry on its
businesses as now conducted and to enter into and perform its obligations under
this Agreement and any document or instrument required to be executed and
delivered on behalf of Brandywine OP hereunder. Brandywine OP has the financial
capability to acquire the Assigned Partnership Interests and Purchased Stock
pursuant to this Agreement.

     4.2   NON-CONTRAVENTION. The execution and delivery of this Agreement and
the performance by Brandywine OP of its obligations hereunder do not and will
not contravene, or constitute a default under, any provisions of Brandywine OP's
Organizational Documents or applicable law or regulation, or any agreement,
judgment, injunction, order, decree or other instrument binding upon Brandywine
OP.

     4.3   LITIGATION. There is no action, suit or proceeding, pending or known
to be threatened, against or affecting Brandywine OP or Brandywine OP in any
court or before any arbitrator or before any Governmental Authority which (a) in
any manner raises any question affecting the validity or enforceability of this
Agreement or any other agreement or instrument to which Brandywine OP is a party
or by which it is bound and that is to be used in connection with, or is
contemplated by, this Agreement, (b) could materially and adversely affect the
business, financial position or results of operations of Brandywine OP, or (c)
could materially and adversely affect the ability of Brandywine OP to perform
its obligations hereunder, or under any document to be delivered pursuant
hereto.

     4.4   BANKRUPTCY. No Act of Bankruptcy has occurred with respect to
Brandywine OP.

     4.5   AUTHORIZATION, EXECUTION AND DISCLOSURE. This Agreement has been duly
authorized by all necessary action on the part of Brandywine OP, has been duly
executed and delivered by Brandywine OP, constitutes the valid and binding
agreement of Brandywine OP and is enforceable in accordance with its terms,
subject to the effect of applicable bankruptcy, insolvency, reorganization,
arrangement, moratorium or other similar laws affecting the rights of creditors
generally.

                                       24
<PAGE>

                                   ARTICLE V.
                              CONDITIONS PRECEDENT

     5.1   AS TO BRANDYWINE OP'S OBLIGATIONS. Brandywine OP's obligations
hereunder are subject to the satisfaction of the following conditions precedent:

           (a) PRENTISS' AND PPL'S DELIVERIES. Prentiss and PPL shall have
delivered to or for the benefit of Brandywine OP, on or before the Closing Date,
all of the documents and other information required of Prentiss pursuant to
SECTIONS 7.2 AND 7.4 hereof.

           (b) REPRESENTATIONS, WARRANTIES AND COVENANTS; OBLIGATIONS OF
PRENTISS AND PPL; CERTIFICATE. All of Prentiss' and PPL's representations and
warranties made in this Agreement shall be true and correct in all material
respects as of the date hereof and as of the date of Closing as if then made;
Prentiss and PPL shall have performed in all material respects all of their
respective covenants and other obligations under this Agreement; and Prentiss
and PPL shall have executed and delivered to Brandywine OP at Closing a
certificate to the foregoing effect.

           (c) TITLE INSURANCE. Good and indefeasible fee simple title to the
Land shall be insurable as such by the Title Company, subject only to Permitted
Title Exceptions as determined in accordance with SECTION 2.4 hereof and
including, without limitation, all applicable deletions of standard exceptions
and endorsements permitted under applicable state law which are customarily
required by institutional investors purchasing property comparable to the
Property.

           (d) CONDITION OF IMPROVEMENTS. The Improvements and the Tangible
Personal Property (including but not limited to the mechanical systems,
plumbing, electrical, wiring, fixtures, heating, air conditioning and
ventilating equipment, elevators, boilers, equipment, roofs, structural members
and furnaces) shall be in the same condition at Closing as they are as of the
date hereof, reasonable wear and tear excepted. None of the Partnerships shall
have removed or caused or permitted to be removed any part or portion of the
Real Property or the Tangible Personal Property without Brandywine OP's prior
written consent unless the same is replaced, prior to Closing, with a similar
item of at least equal suitability, quality and value, free and clear of any
lien or security interest.

           (e) UTILITIES. All of the Utilities shall be installed in and
operating at the Property, and service shall be available for the removal of
garbage and other waste from the Property.

           (f) DUE DILIGENCE MATERIALS. All rent rolls, lists, schedules and
other documents furnished by Prentiss to Brandywine OP under this Agreement
shall be true and correct in all material respects, except for inaccuracies as
to which Brandywine OP was given written notice by Prentiss or PPL or Brandywine
OP otherwise had actual knowledge prior to the end of the Study Period.

           (g) NO ADDITIONAL PROCEEDINGS; TENANT DEFAULTS. Except for matters as
to which Brandywine OP was given written notice by Prentiss or otherwise had
actual knowledge prior to the end of the Study Period, on the Closing Date,
there shall be no (a) litigation pending

                                       25
<PAGE>

or threatened, seeking (i) to enjoin the consummation of the transactions
contemplated hereunder, (ii) to recover title to the Property, or any part
thereof or any interest therein, (iii) to increase substantially ad valorem
taxes theretofore assessed against any of the Property, (iv) to enjoin the
violation of any law, rule, regulation, restrictive covenant or zoning ordinance
that may be applicable to the Property, or (v) claiming defaults or other
liability of any of the Partnerships under Leases by tenants leasing five
percent (5%) or more of the rentable square feet of the Improvements, in the
aggregate or (b) monetary default in excess of thirty (30) days for which a
written notice of default has been given to a tenant and which constitutes an
event of default under, and as defined in, the applicable Lease, or any
threatened or reasonably anticipated material default or other material default
by tenants leasing five percent (5%) or more of the rentable square feet of the
Improvements, in the aggregate.

           (h) ESTOPPEL LETTERS. The estoppel letters to be delivered at Closing
pursuant to SECTION 7.2(h) hereof shall have been obtained and delivered and
shall reflect no facts at material variance with the facts disclosed on the Rent
Roll and records provided to Brandywine OP during the Study Period.

           (i) LENDER ESTOPPEL LETTERS. The lender consent and estoppel letters
to be delivered at Closing pursuant to SECTION 7.2(w) hereof shall have been
obtained and delivered and shall reflect no facts at material variance with the
facts represented and warranted by Prentiss to Brandywine OP hereunder.

           (j) GROUND LESSOR ESTOPPEL LETTERS. Estoppel letters from each Ground
Lessor pursuant to SECTION 7.2(w) hereof.

           (k) ASSIGNMENT OF STOCK BY SHAREHOLDERS. PPL shall have caused the
Shareholders to have transferred to Brandywine OP (or its designee), for no
payment by Brandywine OP, the eleven (11) shares of outstanding common stock in
each of Southpoint Inc. and Valleybrooke Inc., free and clear of all liens,
claims and security interests.

           (l) ESTOPPEL LETTER FROM GORMAN AND KNAUER. The estoppel letter from
Gorman and Knauer pursuant to SECTION 7.2(s).

           (m) OTHER ESTOPPEL LETTERS. Estoppel letters described in SECTION
7.2(t) hereof.

Each of the conditions contained in this SECTION 5.1 are intended for the
benefit of Brandywine OP and may be waived in whole or in part, by Brandywine
OP, but only by an instrument in writing signed by Brandywine OP.

     5.2   AS TO PRENTISS' OBLIGATIONS. Prentiss' obligations hereunder are
subject to the satisfaction of the following conditions precedent:

           (a) BRANDYWINE OP'S DELIVERIES. Brandywine OP shall have delivered to
or for the benefit of Prentiss, on or before the Closing Date, all of the
documents and payments required of Brandywine OP pursuant to SECTIONS 7.3 AND
7.4 hereof.

           (b) REPRESENTATIONS, WARRANTIES AND COVENANTS; OBLIGATIONS OF
BRANDYWINE OP. All of Brandywine OP's representations and warranties made in
this

                                       26
<PAGE>

Agreement shall be true and correct in all material respects as of the date
hereof and as of the date of Closing as if then made and Brandywine OP shall
have performed in all material respects all of its covenants and other
obligations under this Agreement.

Each of the conditions contained in this Section are intended for the benefit of
Prentiss and may be waived in whole or in part, by Prentiss, but only by an
instrument in writing signed by Prentiss.

                                  ARTICLE VI.
                              COVENANTS OF PRENTISS

     To induce Brandywine OP to enter into this Agreement and to acquire the
Assigned Partnership Interests and the Purchased Stock, and to pay the Purchase
Price therefor, Prentiss and PPL, as applicable, covenant and agree to the
following:

     6.1   OPERATING AGREEMENTS. Prentiss shall not permit, prior to the
Closing, any of the Partnerships or the Corporations to enter into any new
management agreement, maintenance or repair contract, supply contract, lease in
which any of the Partnerships or the Corporations is lessee or other agreements
with respect to the Property which cannot be terminated on or before the Closing
Date, nor shall Prentiss permit any of the Partnerships or the Corporations to
enter into any agreements modifying the Operating Agreements in any material
respect, unless (a) any such agreement or modification will not bind the
Partnerships, the Corporations, Brandywine OP or the Property after the date of
Closing or (b) Prentiss has obtained Brandywine OP's prior written consent to
such agreement or modification. Prentiss agrees to cause the Partnerships and
the Corporations to cancel and terminate effective as of the Closing Date all
property management agreements affecting the Property or any portion thereof and
the Operating Agreements to be terminated pursuant to the last sentence of
SECTION 3.7 hereof.

     6.2   WARRANTIES AND GUARANTIES. Prentiss shall not permit, prior to the
Closing, any of the Partnerships or the Corporations before or after Closing to
release or modify any Warranties and Guaranties, if any, except with the prior
written consent of Brandywine OP.

     6.3   INSURANCE. Prior to the Closing Date, Prentiss shall cause the
Partnerships and the Corporations to pay all premiums on, and shall not cancel
or voluntarily allow to expire, any of Prentiss' Insurance Policies unless such
policy is replaced, without any lapse of coverage, by another policy or policies
providing coverage at least as extensive as the policy or policies being
replaced. Prentiss hereby indemnifies and holds Brandywine OP harmless from and
against all losses, costs, damages and expenses resulting from actions involving
bodily or personal injury or property damage in or about any of the Property
that occurred prior to the Closing Date, regardless of when the claim was made,
but only to the extent coverage under the applicable Insurance Policy or
Policies is not sufficient and paid, and this indemnity shall survive the
Closing Date.

     6.4   OPERATION OF PROPERTY PRIOR TO CLOSING. Prentiss and Brandywine OP
represent, warrant, covenant and agree with Brandywine OP that, between the date
of this Agreement and the date of Closing:

                                       27
<PAGE>

           (a) Subject to the restrictions contained herein, Prentiss shall
cause the Partnerships to operate the Property in the same manner in which the
Partnerships operated the Property prior to the execution of this Agreement, so
as to keep the Property in good condition, reasonable wear and tear excepted.

           (b) Prentiss shall cause the Partnerships to maintain their
respective books of account and records in the usual, regular and ordinary
manner, in accordance with sound accounting principles applied on a basis
consistent with the basis used in keeping such books in prior years.

           (c) Prentiss shall cause the Partnerships to maintain in full force
and effect all Insurance Policies.

           (d) Prentiss shall cause the Partnerships to punctually perform and
discharge all obligations and undertakings of the Partnerships under the Leases
and shall not permit a default by the Partnerships to occur thereunder.

           (e) Prentiss shall cause the Partnerships to use and operate the
Property in compliance with Applicable Laws and the requirements of any
mortgage, ground lease, Lease, Operating Agreement and Insurance Policy
affecting the Property.

           (f) Prentiss shall cause to be paid prior to delinquency all ad
valorem and other taxes due and payable with respect to the Property or its
operation.

           (g) Without the express prior written consent of Brandywine OP (which
consent shall not be unreasonably withheld and shall be deemed to have been
given if Brandywine OP fails to respond to a written request from Prentiss for
such consent within two (2) business days following Brandywine OP's receipt of
any such request), none of the Partnerships shall: (i) enter into new Leases of
any kind or nature affecting the Property; or (ii) grant a renewal or extension
of any existing Lease, or consent to any assignment, sublease or expansion of
any existing lease or portion thereof which, by the terms of any such Lease,
requires any of the Partnerships' prior consent as a condition to any such
renewal, extension, assignment, sublease or expansion. Prentiss shall not permit
any of the Partnerships, without the express written consent of Brandywine OP,
in any manner to change, modify, extend, renew or terminate any Lease except as
required by the terms thereof, or waive in any material respect any of the
tenant's obligations under any Lease; provided, Leases with Prentiss' management
company may be terminated on or before the Closing Date without the prior
consent of Brandywine OP. Prentiss shall not permit any of the Partnerships to
apply all or any part of the security or damage deposit of a tenant under any
Lease to obligations of such tenant, unless such tenant has vacated its portion
of the Property as of the Closing Date. Notwithstanding the foregoing,
Brandywine OP hereby approves the new Leases which have been entered into by any
of the Partnerships and costs associated therewith, as more particularly
described in SCHEDULE 6.4(g) hereto.

           (h) Prentiss shall cause all debts and liabilities for labor,
materials, services and equipment incurred in the construction, operation and
development of the Property, including leasehold improvements, to be promptly
paid.

                                       28
<PAGE>

           (i) Neither Prentiss, any of the Partnerships, the Corporations nor
Prentiss' managing agent shall (1) make any agreements which shall be binding
upon Brandywine OP, the Partnerships or the Corporations, or (2) reduce, or
cause to be reduced any rents or any other revenues over which Prentiss has
operational control.

           (j) Prentiss shall promptly deliver to Brandywine OP upon Brandywine
OP's request such reports showing the revenue and expenses of the Property the
Partnerships and the Corporations as Prentiss customarily keeps or receives
internally for its own use.

           (k) Except as required by the terms thereof or hereof, Prentiss shall
not permit any of the Partnerships or the Corporations in any manner to change,
modify, extend, renew or terminate any Operating Agreement which would be
binding on Brandywine OP, the Partnerships or the Corporations without the
express written consent of Brandywine OP.

           (l) Prentiss shall promptly advise Brandywine OP of any litigation,
arbitration or administrative hearing concerning or affecting the Property, the
Partnerships or the Corporations of which Prentiss obtains actual knowledge.

           (m) Prentiss shall cause the Partnerships to keep the Existing Notes
current, shall comply with the terms and provisions of the Existing Notes and
the Existing Liens and shall immediately send Brandywine OP copies of all
correspondence received from any of the holders of the Existing Notes. Prentiss
shall not permit any of the Partnerships to modify any provisions of the
Existing Notes or the Existing Liens.

           (n) PPL shall cause Southpoint Inc. and Valleybrooke Inc. to maintain
each Ground Lease in full force and effect and shall not permit Southpoint Inc.
or Valleybrooke Inc. to enter into any modification or amendment to any Ground
Lease without the prior written consent of Brandywine OP.

     6.5   NO MARKETING. Prentiss shall not permit any of the Partnerships to
market the Property for sale or enter into discussions or negotiations with
potential purchasers of the Property unless this Agreement has been terminated
pursuant to its terms.

     6.6   PUT/CALL AGREEMENT. Prentiss and PPL hereby grant to Brandywine OP
(or its designee) the irrevocable right and option to acquire any or all of the
Retained Interests owned by it, free and clear of all liens and encumbrances, at
any time upon three (3) days prior written notice; provided that in no event may
Brandywine OP (or its designee) exercise its option to acquire less than all of
the Retained Interests owned by Prentiss in any given Partnership or the common
shares of PPL in each of Southpoint Inc. and Valleybrooke Inc. If Brandywine OP
(or its designee) exercises its purchase option prior to the date that is one
day after the third anniversary of the Closing Date, then the exercise notice
shall contain the agreement of Brandywine OP to pay all Pennsylvania real estate
transfer taxes that may become payable upon the transfer of any or all of such
Retained Interests as a result of the option being exercised prior to such date.
At any time after the date that is one day after the third anniversary of the
Closing Date, Prentiss may require Brandywine OP (or its designee) to acquire
all and not less than all of the Retained Interests, free and clear of all liens
and encumbrances, at any time upon three (3) days prior written notice. The
aggregate price payable by Brandywine OP (or its designee) for

                                       29
<PAGE>

the Retained Interests (whether due to the exercise by Brandywine OP of the
purchase option or to the exercise by Prentiss of the sale option), which shall
be payable in immediately available funds, shall be equal to eleven percent
(11%) of the amount by which the Purchase Price exceeds the outstanding
principal balance of the Existing Notes on the Closing Date (the "AGGREGATE
PRICE") minus the aggregate amount of distributions, if any, made by the
Partnerships to Prentiss on account of the Retained Interests. Set forth on
SCHEDULE 6.6 attached hereto is an allocation of the Aggregate Price among the
Retained Interests, which shall be applicable in the event that Brandywine OP
exercises its option to acquire less than all of the Retained Interests. In
addition, Prentiss hereby grants to Brandywine OP (or its designee) the
irrevocable right and option to acquire the entire Additional Retained Interest,
free and clear of all liens and encumbrances, at any time after August 25, 2001,
and Prentiss agrees to take such actions as may be permitted under the Call
Option Agreement (Cash) dated as of August 25, 1998 (the "Call Agreement") among
Gorman, Knauer and Prentiss to provide for the acquisition by Brandywine OP (or
its designee) of the entire Additional Retained Interest. In addition,
Brandywine OP hereby agrees to acquire, upon the request of Prentiss, the entire
Additional Retained Interest, free and clear of all liens and encumbrances, at
any time after August 25, 2001. The price payable by Brandywine OP (or its
designee) to Prentiss on account of the acquisition by Brandywine OP (or its
designee) of the Additional Retained Interest shall be equal to eleven percent
(11%) of the amount by which the Purchase Price exceeds the outstanding
principal balance of the Existing Notes on the Closing Date and shall be payable
by Brandywine OP pursuant to a promissory note in the form of the Note referred
to in SECTION 1.1 with the exception of the principal amount thereof (which
shall be the foregoing dollar amount) and the fact that interest shall accrue
thereon from the date of issuance thereof. Prentiss shall pay to Gorman and
Knauer all amounts required to be paid to them under the Call Agreement in
connection with the acquisition of the Additional Retained Interest. The
provisions of this SECTION 6.6 shall survive the Closing Date.

     6.7   TAX RETURNS. Prentiss shall deliver to Brandywine OP, for its review
and comment, copies of federal income tax returns for the Partnerships
attributable to the period from January 1, 2001 to the Closing Date prior to the
date such tax returns are filed with the Internal Revenue Service. Prentiss
shall be responsible for the costs to prepare the foregoing tax returns.

     6.8   GROUND LESSOR ESTOPPELS. Prentiss shall cause each Ground Lessor to
deliver the estoppel certificates described in SECTION 7.2(w) hereof.

     6.9   LEASED PROPERTY. Prentiss shall be solely responsible for all
obligations relating to the Leased Property, and neither the Partnerships nor
Brandywine OP shall have any obligations with respect thereto. The provisions of
this SECTION 6.9 shall survive the Closing.

The foregoing covenants of Prentiss and PPL are for the benefit of Brandywine OP
or its assignee of its rights under this Agreement.

                                  ARTICLE VII.
                                     CLOSING

     7.1   CLOSING. The Closing shall occur within five (5) days after the
conditions precedent set forth in SECTIONS 5.1 AND 5.2 have been satisfied. As
more particularly described below, at the Closing the parties hereto will meet
to (i) execute all of the documents required to

                                       30
<PAGE>

be delivered in connection with the transactions contemplated hereby (the
"CLOSING DOCUMENTS"), (ii) deliver the same to Escrow Agent, and (iii) take all
other action required to be taken in respect of the transactions contemplated
hereby. The Closing will occur at the offices of the Escrow Agent. At the
Closing, the Title Company shall update the title to the Property and, provided
there has been no change in the status of title as reflected in the Title
Commitment and Survey which has not been waived by Brandywine OP pursuant to
SECTION 2.4(d) hereof, and Escrow Agent shall release and date, where
appropriate, the Closing Documents in accordance with the joint instructions of
Prentiss and Brandywine OP and shall send, by wire transfer, all sums, if any,
owing to Prentiss or Brandywine OP hereunder to Prentiss or Brandywine OP, as
applicable. At Closing, the Escrow Agent shall additionally send, by wire
transfer to Prentiss all sums owing to Prentiss hereunder. As provided herein,
the parties hereto will agree upon adjustments and prorations to certain items
which cannot be exactly determined at the Closing and will make the appropriate
adjustments with respect thereto. Notwithstanding anything herein to the
contrary, if the Closing Date does not occur by April 30, 2001, and the
provisions of Section 9.3 or 9.5 are not applicable, then either party may
terminate this Agreement by notice to the other party hereto, in which event
neither party shall have any further obligation to the other except for the
indemnities and other provisions of this Agreement which expressly survive a
termination of this Agreement, and the Deposit, less the Independent
Consideration, shall be promptly refunded to Brandywine OP.

     7.2   PRENTISS' DELIVERIES. At the Closing, Prentiss or PPL, as applicable,
shall deliver to Escrow Agent all of the following instruments, each of which
shall have been duly executed and, where applicable, acknowledged and/or sworn
on behalf of Prentiss or PPL, as applicable, and shall be dated as of the
Closing Date:

           (a) The certificate required by SECTION 5.1(b) hereof.

           (b) The Assignment of Partnership Interests.

           (c) Intentionally Deleted.

           (d) Amendments to each of the certificates of limited partnership for
the Partnerships showing Brandywine OP (or its designee) as the successor to
Prentiss as a general partner in each of the Partnerships and the withdrawal of
Prentiss as the general partner of each of the Partnerships with regard to the
Assigned Partnership Interests only (the "AMENDMENTS TO CERTIFICATES OF LIMITED
PARTNERSHIP").

           (e) Certificates of subsistence for each of the Partnerships,
Valleybrooke Inc. and Southpoint Inc. and certified copies of the articles of
incorporation for the Corporations and certificates of limited partnership of
each of the Partnerships from the Pennsylvania Secretary of State. Prentiss
shall deliver certified copies of the bylaws of the Corporations.

           (f) An updated certified Rent Roll dated as of the date preceding the
Closing Date.

           (g) Either (i) an estoppel letter in the form of EXHIBIT C hereto
dated not more than thirty (30) days prior to the Closing Date (a) from each of
the tenants under the Leases covering 7,500 square feet or more, and (b) from
tenants leasing, in the aggregate, at least

                                       31
<PAGE>

seventy-five percent (75%) of the remainder of the Improvements, or (ii) an
estoppel letter executed by Prentiss certifying to the matters specified in
EXHIBIT C hereto for any tenant which does not execute an estoppel letter. Any
estoppel letter provided by Prentiss for a Lease pursuant to CLAUSE (ii) above
shall state that Prentiss shall have no liability thereunder if Prentiss
subsequently provides to Brandywine OP an estoppel letter in the form of EXHIBIT
C from the tenant under such Lease.

           (h) Such agreements, affidavits or other documents as may be required
by the Title Company to issue the Owner's Title Policy subject only to the
Permitted Title Exceptions and to eliminate such standard exceptions and to
issue the endorsements thereto which are customarily required by institutional
investors purchasing property comparable to the Property, including, without
limitation, a non-imputation endorsement.

           (i) An updated Title Commitment issued by the Title Company, dated as
of the date and time of Closing, subject only to the Permitted Title Exceptions.

           (j) The FIRPTA Certificates.

           (k) All original Warranties and Guaranties in Prentiss' possession or
reasonably available to Prentiss.

           (l) To the extent in Prentiss' possession or reasonably available to
Prentiss, a valid, final and unconditional certificate of occupancy for the Real
Property and Improvements, issued by the appropriate Governmental Authority and,
if required by Applicable Laws, transferred to Brandywine OP.

           (m) Executed originals of all Leases, leases of Leased Property,
permits and, to the extent in Prentiss' possession or control, Authorizations
transferred or assigned to Brandywine OP at Closing as required hereunder and
any other documents or instruments affecting the Property or the ownership and
operation thereof.

           (n) All current real estate and personal property tax bills in
Prentiss' possession or under its control.

           (o) All books, records, operating reports, appraisal reports, files
and other materials in Prentiss' possession or control which are necessary in
Brandywine OP's reasonable discretion to maintain continuity of operation of the
Property. Brandywine OP covenants to permit Prentiss to photocopy any of the
matters described in this SUBPARAGRAPH 7.2(O) for a period of three (3) years
following the Closing Date, which covenant of Brandywine OP shall survive for
such three (3) year period.

           (p) A current UCC Report showing no financing statements by any of
the Partnerships as Debtor covering the Property, except in favor of the holders
of the Existing Notes.

           (q) All keys to all locks on the Property in the possession of
Prentiss, together with an accounting for such keys in the possession of others.

                                       32
<PAGE>

           (r) Intentionally deleted.

           (s) Certified copies of a incumbency certificate and resolutions
authorizing the execution by Prentiss and PPL of this Agreement and all
documents to be executed by Prentiss and PPL on the Closing Date.

           (t) Estoppel letters from each owners association created pursuant to
restrictive covenants or deed restrictions affecting the Real Property
certifying that (i) the Real Property complies with such restrictive covenants
or deed restrictions, and (ii) no assessments are due and owing with respect to
the Real Property, and estoppel letters from adjoining property owners who are
parties to adjoining landowner agreements binding on any portion of the Real
Property; provided, Prentiss may execute an estoppel letter certifying to the
foregoing matters for an owners association or property owner that does not
execute any such estoppel letter, which estoppel letter shall continue in effect
unless and until the applicable estoppel letter is subsequently provided from
any such owners association or property owner.

           (u) Any other document or instrument reasonably requested by
Brandywine OP in connection with the transactions contemplated hereby.

           (v) An estoppel certificate and consent executed by the present
holders of each of the Existing Notes substantially in the form of EXHIBIT F
attached hereto. Any and all fees and charges in connection with obtaining such
written consent or approval (specifically including, but not limited to, loan
transfer fees) shall be at Prentiss' sole cost and expense.

           (w) An estoppel certificate executed by each Ground Lessor in a form
reasonably satisfactory to Prentiss and Brandywine OP.

           (x) Written notice executed by Prentiss notifying all interested
parties, including, without limitation, all tenants under the Leases, that
Brandywine OP has replaced Prentiss as general partner of the Partnerships and
directing that all payments, inquiries and the like to the Partnerships be
forwarded to Brandywine OP (as the general partner) at the address to be
provided by Brandywine OP.

           (y) The originals of the Assumed Operating Agreements.

     7.3   BRANDYWINE OP'S DELIVERIES. At the Closing, Brandywine OP shall
deliver to Escrow Agent the following instruments, each of which shall have been
duly executed and, where applicable, acknowledged and/or sworn on behalf of
Brandywine OP and shall be dated as of the Closing Date:

           (a) The Note.

           (b) The Assignment of Partnership Interests.

           (c) Intentionally Deleted.

           (d) The amendments to certificates of limited partnership referred to
in SECTION 7.2(d) above.

                                       33
<PAGE>

           (e) Any other document or instrument reasonably requested by Prentiss
or PPL in connection with the transactions contemplated hereby.

     7.4   MUTUAL DELIVERIES. At the Closing, Brandywine OP and Prentiss shall
mutually execute and deliver each to the other:

           (a) A final closing statement reflecting the adjustments and
prorations required hereunder and the allocation of income and expenses required
hereby.

           (b) Such other and further documents, papers and instruments as may
be reasonably required by the parties hereto in connection with the transactions
contemplated hereby or their respective counsel.

     7.5   CLOSING COSTS. Except as is explicitly provided in this Agreement,
each party hereto shall pay its own legal fees and expenses. Prentiss shall pay
for the costs associated with the releases of any deeds of trust, mortgages and
other financing encumbering the Property that Prentiss is to cause to be
released pursuant to this Agreement and for any costs associated with any
corrective instruments. Prentiss shall pay all costs for title searches, tax
certificates and all premiums for the issuance of the Title Policy; all costs of
providing the matters described in SECTIONS 2.4(b) AND (d) to Brandywine OP; and
one-half (1/2) of any escrow fees or similar charges of the Escrow Agent. PPL
shall pay all costs payable to the Shareholders in connection with the
assignment to Brandywine OP (or its designee) of the shares of common stock in
each of Southpoint Inc. or Valleybrooke Inc. described in SECTION 5.1(l) hereof.
Brandywine OP shall pay one-half (1/2) of any escrow fees or similar charges of
the Escrow Agent. Prentiss shall pay all prepayment penalties and other costs
and expenses payable in connection with debt which Prentiss is required to
prepay on the Closing Date, and Prentiss shall pay all debt transfer and similar
fees associated with the Existing Notes and the Existing Liens and the premium
for a downdate endorsement to loan policies issued to the holders of the
Existing Notes if such endorsements are required by such holders. Prentiss shall
pay all assessments levied or pending against the Property as of the Closing
Date. To the extent that state and local transfer taxes or stamps are imposed in
connection with the transactions under this Agreement for any reason whatsoever,
the cost of such taxes or stamps shall be borne one-half by Brandywine OP and
one-half by Prentiss, except that Brandywine OP shall be solely responsible for
such transfer taxes if it elects to exercise its call right under any of the
Put/Call Agreements prior to the date that is three (3) years and one (1) day
following the Closing Date. Brandywine OP shall pay for the premium for the
Title Policy in excess of the sums payable by Prentiss pursuant to this SECTION
7.5. All other expenses incurred by Prentiss or Brandywine OP with respect to
the Closing shall be borne and paid for exclusively by the party incurring same,
without reimbursement, except to the extent otherwise specifically provided
herein.

     7.6   REVENUE AND EXPENSE ALLOCATIONS. All revenues (including operating
expense escalations) and expenses with respect to the Property, the Corporations
and the Partnerships, and applicable to the period of time before and after
Closing, determined in accordance with sound accounting principles consistently
applied, shall be allocated between Prentiss and Brandywine OP as provided
herein. Prentiss shall be entitled to all revenue and shall be responsible for
all expenses for the period of time up to but not including the Closing Date,
and Brandywine OP shall be entitled to all revenue and shall be responsible for
all expenses for the

                                       34
<PAGE>

period of time from, after and including the date of Closing. Such adjustments
shall be shown on the closing statements (with such supporting documentation as
the parties hereto may require being attached as exhibits to the closing
statements) and shall increase or decrease (as the case may be) the Purchase
Price payable by the parties hereto. Without limiting the generality of the
foregoing, the following items of revenue and expense shall be allocated at
Closing:

           (a) Current rents.

           (b) Real estate and personal property taxes for the Property for the
current calendar year 2001.

           (c) Revenue and expenses under the Assumed Operating Agreements.

           (d) Utility charges (including, but not limited to, charges for
water, sewer and electricity).

           (e) Municipal or other governmental improvement liens, which shall be
paid by Prentiss at Closing where the work has physically commenced, and which
shall be assumed by Brandywine OP at Closing where the work has been authorized,
but not physically commenced.

           (f) All other revenues (including CAM charges) and expenses of the
Property.

           (g) Interest on the Existing Notes.

Brandywine OP shall receive a credit for purposes of calculating closing
prorations for the total of (i) prepaid rents and (ii) unforfeited security
deposits together with interest thereon held by any of the Partnerships under
Leases.

The amount of any escrow accounts held by the holder(s) of the Existing Notes
shall be transferred to Brandywine OP by Prentiss and paid for by Brandywine OP.

Prentiss shall pay or cause to be paid all real estate taxes and installments
for special assessments (prorated to the Closing Date) for the Property due and
payable in, or deferred with respect to the years prior to, the year in which
the Closing occurs. All installments for special assessments (prorated to the
Closing Date) pending, levied or due and payable on or prior to the Closing Date
shall be paid by Prentiss on or before the Closing Date. All subdivision and
platting costs and expenses heretofore incurred by Prentiss or any of the
Partnerships, including, without limitation, all subdivision exactions, fees and
costs and all dedication of land for parks and other public uses or payment of
fees in lieu thereof, shall be paid by Prentiss on or prior to the Closing Date.

If accurate allocations cannot be made at Closing because current bills are not
obtainable (as, for example, in the case of utility bills and/or real estate or
personal property taxes), the parties shall allocate such revenue or expenses at
Closing on the best available information, subject to adjustment upon receipt of
the final bill or other evidence of the applicable revenue or expense. The
obligation to make the adjustment shall survive the closing of the transaction
contemplated by this Agreement. Any revenue received or expense incurred by
Prentiss, any of the Partnerships or Brandywine OP with respect to the Property
after the Closing Date shall be

                                       35
<PAGE>

promptly allocated in the manner described herein and the parties shall promptly
pay or reimburse any amount due. Prentiss shall calculate and deliver to
Brandywine OP for its approval and its transmittal to tenants under Leases,
reconciliations of operating costs for the calendar year 2000, and Brandywine OP
shall inform the tenants that Prentiss prepared such reconciliations and can be
contacted to discuss any questions concerning such reconciliations. The
proration provisions of this Agreement shall survive the closing of the
transaction contemplated hereby for a period of eighteen (18) months.

     7.7   DELINQUENT RENTS. Any rents or other amounts which are delinquent as
of the Closing shall not be adjusted or prorated at Closing, but Brandywine OP
shall make a reasonable attempt to collect such amounts for the benefit of
Prentiss after the Closing; provided, however, that nothing contained herein
shall be construed to require Brandywine OP to institute any lawsuit or other
proceedings to collect such delinquent amounts. In this connection, the first
monies collected by Brandywine OP from tenants or other persons owing delinquent
rents or other amounts shall be applied to Brandywine OP's costs of collection,
then to the current rents or obligations of such person to Brandywine OP, and
the balance, if any, shall be delivered to Prentiss to the extent of the
delinquency. Prentiss shall be permitted to bring collection suits against
tenants owing rent to any of the Partnerships for periods prior to the Closing
Date that is more than thirty (30) days in arrears; however, Prentiss may not
bring any eviction actions against any tenants under any of the Leases.

     7.8   COSTS ASSOCIATED WITH CERTAIN LEASING ACTIVITIES. Except as otherwise
expressly set forth in this SECTION 7.8, all refurbishment allowances, tenant
improvement costs and leasing commissions owing or which could become due and
owing with respect to Leases entered into on or before the Closing Date shall be
paid by Prentiss when due, and Prentiss shall indemnify and hold harmless
Brandywine OP and the Partnerships for claims brought against the Property, the
Partnerships or Brandywine OP arising therefrom, which indemnity shall survive
the Closing. Notwithstanding the foregoing: (i) Brandywine OP shall pay to
Prentiss at the Closing an amount equal to the cost of all (x) leasing
commissions paid by Prentiss, prior to the Closing Date, to brokers other than
affiliates of Prentiss and (y) capital improvement costs incurred and paid by
Prentiss prior to the Closing Date in completing tenant improvements pursuant to
(in the case of both (x) and (y)) (a) Leases entered into by any of the
Partnerships on or after January 1, 2001 and other Leases, which are described
on SCHEDULE 6.4(g) or which have been approved or deemed approved by Brandywine
OP pursuant to SECTION 6.4(g); (b) renewals, extensions or expansions of
existing Leases expressly requiring the approval of Prentiss as a condition to
the exercise of such options which are exercised on or after January 1, 2001,
which either are described on SCHEDULE 6.4(g) or have been approved or deemed
approved by Brandywine OP pursuant to SECTION 6.4(g); and (c) renewals,
extensions or expansions of existing Leases not requiring the approval of
Prentiss as a condition to the exercise of such options which have been
exercised on or after January 1, 2001; and (ii) Brandywine OP shall be
responsible for refurbishment allowances, tenant improvement costs and leasing
commissions shown in the Rent Roll or contained in Leases delivered pursuant to
SECTION 2.4(b)(1) hereof that have not previously been paid by Prentiss but are
payable following the Closing Date under existing Leases on or after January 1,
2001 or which are contained in Leases entered into between January 1, 2001 and
the Closing Date which are described on SCHEDULE 6.4(g) or which have been
approved or deemed approved pursuant to SECTION 6.4(g) hereof. The provisions of
this SECTION 7.8 shall survive the Closing Date.

                                       36
<PAGE>

                                 ARTICLE VIII.
                               GENERAL PROVISIONS

     8.1   CONDEMNATION. In the event of any actual or threatened taking,
pursuant to the power of eminent domain, of all or any portion of the Real
Property, or any proposed sale in lieu thereof, Prentiss shall give written
notice thereof to Brandywine OP promptly after Prentiss learns or receives
notice thereof. If all or any part of the Real Property is, or is to be, so
condemned or sold, Brandywine OP shall have the right to terminate this
Agreement pursuant to SECTION 9.3 hereof. If Brandywine OP elects not to
terminate this Agreement, all proceeds, awards and other payments arising out of
such condemnation or sale (actual or threatened) shall be retained by the
Partnerships at Closing and there shall be no reduction in the Purchase Price.
Prentiss shall not, and shall not permit the Partnerships or the Corporations
to, settle or compromise any such proceeding without Brandywine OP's written
consent. If Brandywine OP elects to terminate this Agreement by giving Prentiss
written notice thereof prior to the Closing, the Deposit shall be promptly
returned to Brandywine OP and all rights and obligations of Prentiss, PPL and
Brandywine OP hereunder (except those set forth herein which expressly survive a
termination of this Agreement) shall terminate immediately.

     8.2   RISK OF LOSS. The risk of any loss or damage to the Property prior to
the recordation of the Deed shall remain upon Prentiss. If any such loss or
damage occurs prior to Closing which exceeds an amount equal to five percent
(5%) of the Purchase Price, Brandywine OP shall have the right to terminate this
Agreement pursuant to SECTION 9.3 hereof. If Brandywine OP elects not to
terminate this Agreement pursuant to the immediately preceding sentence or a
loss or damage occurs prior to Closing which does not exceed five percent (5%)
of the Purchase Price, all insurance proceeds and rights to proceeds arising out
of such loss or damage, less the reasonable expenses incurred in collecting such
proceeds and, to the extent payable from insurance proceeds, reasonable expenses
incurred in securing the Property following a casualty, shall be retained by the
Partnerships at Closing, and Brandywine OP shall receive as a credit against the
Purchase Price in the amount of any deductibles under the policies of insurance
covering such loss or damage and there shall be no further reduction in the
Purchase Price; provided, however, Prentiss shall be entitled to retain rent
loss insurance proceeds received that are attributable to periods prior to the
Closing Date. If Brandywine OP elects to terminate this Agreement pursuant to
this SECTION 8.2 by giving Prentiss written notice thereof prior to the Closing,
the Deposit shall be promptly returned to Brandywine OP and all rights and
obligations of Prentiss and Brandywine OP hereunder (except those set forth
herein which expressly survive a termination of this Agreement) shall terminate
immediately.

     8.3   BROKER. There is no real estate broker involved in this transaction.
Brandywine OP warrants and represents to Prentiss that Brandywine OP has not
dealt with any real estate broker in connection with this transaction, nor has
Brandywine OP been introduced to the Property or to Prentiss by any real estate
broker, and Brandywine OP shall indemnify Prentiss and hold Prentiss harmless
from and against any claims, suits, demands or liabilities of any kind or nature
whatsoever arising on account of the claim of any other person, firm or
corporation to a real estate brokerage commission or a finder's fee or a
financial advisory fee as a result of having dealt with Brandywine OP, or as a
result of having introduced Brandywine OP to Prentiss or to the Property. In
like manner, Prentiss warrants and represents to Brandywine OP that Prentiss has
not dealt with any real estate broker in connection with this

                                       37
<PAGE>

transaction, nor has Prentiss been introduced to Brandywine OP by any real
estate broker, and Prentiss shall indemnify Brandywine OP and save and hold
Brandywine OP harmless from and against any claims, suits, demands or
liabilities of any kind or nature whatsoever arising on account of the claim of
any person, firm or corporation to a real estate brokerage commission or a
finder's fee or a financial advisory fee as a result of having dealt with
Prentiss in connection with this transaction. This provision shall survive any
termination of this Agreement and a closing of the transaction contemplated
hereby.

                                  ARTICLE IX.
            LIABILITY OF BRANDYWINE OP; INDEMNIFICATION BY PRENTISS;
                           DEFAULT; TERMINATION RIGHTS

     9.1   LIABILITY OF BRANDYWINE OP. Except for obligations expressly assumed
or agreed to be assumed by Brandywine OP hereunder, Brandywine OP is not
assuming any obligations of Prentiss, the Partnerships or the Corporations or
any liability for claims arising out of any act, omission or occurrence which
occurs, accrues or arises prior to the Closing Date (except to the extent such
assumption occurs as a matter of law), and Prentiss hereby indemnifies and holds
Brandywine OP, the Partnerships and the Corporations harmless from and against
any and all claims, costs, penalties, damages, losses, liabilities and expenses
(including reasonable attorneys' fees) that may at any time be incurred by
Brandywine OP, the Partnerships and the Corporations as a result of (a)
obligations of Prentiss (i) not expressly assumed or agreed to be assumed by
Brandywine OP hereunder or (ii) which Brandywine OP is assuming as a matter of
law, but not otherwise expressly assuming hereunder or under any document to be
executed on the Closing Date that relate solely to any act, omission or
occurrence which occurs, accrues or arises prior to the Closing Date, or (b)
acts, omissions or occurrences which occur, accrue or arise prior to the Closing
Date. Brandywine OP hereby indemnifies and holds Prentiss harmless from and
against any and all claims, costs, penalties, damages, losses, liabilities and
expenses (including reasonable attorneys' fees) that may at any time be incurred
by Prentiss as a result of acts, omissions or occurrences relating to the
Property, the Partnerships and the Corporation arising and accruing from and
after the Closing Date. The provisions of this Section shall survive the Closing
of the transaction contemplated hereby.

     9.2   INDEMNIFICATION BY PRENTISS. Prentiss hereby indemnifies and holds
Brandywine OP and Brandywine OP's officers, partners, directors, shareholders,
agents and employees (collectively, the "INDEMNIFIED PARTIES") harmless from and
against any and all claims, costs, penalties, damages, losses, liabilities and
expenses (including reasonable attorneys' fees) that may at any time be incurred
by Brandywine OP, whether incurred before or after Closing, as a result of any
inaccuracy or breach by Prentiss or PPL of any of its representations,
warranties, covenants or obligations set forth herein or in any other document
delivered by Prentiss or PPL pursuant hereto except for any breach or inaccuracy
of any representation or warranty as to which Prentiss has given Brandywine OP
written notice prior to Closing of the untruth or inaccuracy or of which
Brandywine OP otherwise had actual knowledge prior to the Closing and
nevertheless elected to consummate the Closing; provided, however, the foregoing
knowledge limitation on Prentiss' indemnity shall not limit Brandywine OP's
remedy described in SECTION 9.3(a)(ii) hereof or in the last sentence of SECTION
9.3 hereof. The provisions of this Section shall survive the Closing of the
transaction contemplated hereby as provided in SECTION 10.11 hereof, and shall,
following any assignment of this Agreement by Brandywine OP,

                                       38
<PAGE>

continue in favor of the Indemnified Parties of the original Brandywine OP
hereunder as well the Indemnified Parties of any assignee during said survival
period.

     9.3   DEFAULT BY PRENTISS/FAILURE OF CONDITIONS PRECEDENT. If any condition
set forth herein for the benefit of Brandywine OP cannot or will not be
satisfied prior to Closing, or upon the occurrence of any other event that would
entitle Brandywine OP to terminate this Agreement and its obligations hereunder,
and if Prentiss fails to cure any such matter or satisfy that condition within
ten (10) business days after notice thereof from Brandywine OP (or such other
time period as may be explicitly provided for herein), Brandywine OP, at its
option, may elect (a) to terminate this Agreement, in which event (i) the
Deposit, less the Independent Consideration, shall be promptly returned to
Brandywine OP, (ii) if the condition which has not been satisfied is a breach of
a representation, warranty or covenant known by Prentiss to have been inaccurate
or misleading when made, then Prentiss shall be obligated upon demand to
reimburse Brandywine OP for Brandywine OP's actual out-of-pocket inspection,
financing and other costs related to Brandywine OP's entering into this
Agreement, inspecting the Property and preparing for a Closing of the
transaction contemplated hereby, including, without limitation, Brandywine OP's
attorneys' fees incurred in connection with the preparation, negotiation and
execution of this Agreement and in connection with Brandywine OP's due diligence
review, audits and preparation for a Closing up to an aggregate amount equal to
$100,000.00; provided, the foregoing shall not limit or include the sums which
may be payable by Prentiss pursuant to SECTION 9.6 below, and (iii) all other
rights and obligations of Prentiss, PPL and Brandywine OP hereunder (except
those set forth herein which expressly survive a termination of this Agreement)
shall terminate immediately; (b) elect to proceed to Closing; or (c) seek to
enforce Prentiss' and PPL's obligations hereunder by specific performance. If
Brandywine OP elects to proceed to Closing and there is either a
misrepresentation or breach of a warranty by Prentiss or PPL (other than a
breach of a representation or warranty of which Brandywine OP had actual
knowledge prior to the Closing and nevertheless elected to consummate the
Closing) or the breach of a covenant by Prentiss or PPL or a failure by Prentiss
or PPL to perform its respective obligations hereunder first discovered by
Brandywine OP after the Closing Date, Brandywine OP shall retain all remedies
accruing as a result thereof, including, but not limited to, the remedy of
specific performance of Prentiss' or PPL's covenants and obligations and the
remedy of the recovery of all reasonable damages resulting from Prentiss' or
PPL's breach of warranty or covenant. Notwithstanding the foregoing, if the
condition which has not been satisfied is a breach of one or more
representations and warranties by Prentiss or PPL in this Agreement and/or in
any of the other documents executed of even date herewith between Prentiss and
Brandywine OP or any of their respective affiliates (the "OTHER DOCUMENTS"),
Brandywine OP has elected to proceed to Closing, and Brandywine OP can
reasonably quantify the damage resulting from such breach of representations and
warranties with reasonable support for such calculation of damages, then (i) if
the aggregate damage is no greater than $150,000.00 (the "FIRST THRESHOLD
LEVEL"), then neither Prentiss nor PPL shall have any obligation to either cure
such breaches of representations and warranties or pay Brandywine OP at Closing
in the event Brandywine OP elects to close the transaction described in this
Agreement and under the Other Documents; (ii) if such aggregate damage is
greater than the First Threshold Level but less than $1,500,000.00, then
Prentiss must prior to the Closing Date either cure such breaches of
representations and warranties to the reasonable satisfaction of Brandywine OP
or Prentiss shall pay Brandywine OP at the Closing an amount equal to the actual
damages as reasonably determined by Brandywine OP as aforesaid, less the First
Threshold Level; and (iii) in the event

                                       39
<PAGE>

the aggregate damages resulting from such breaches of representations and
warranties would exceed $1,500,000.00, then Brandywine OP may either (A)
terminate this Agreement and the Other Documents, in which event the Deposit
(less the Independent Consideration) shall be promptly refunded, or (B)
Brandywine OP may close the transaction as described in this Agreement and the
Other Documents and Brandywine OP shall be paid by Prentiss the amount of
$1,350,000.00, which amount shall be the maximum aggregate amount payable by
Prentiss and PPL under the last sentence of SECTION 9.3 of this Agreement and
all of the Other Documents.

     9.4   INDEMNIFICATION BY BRANDYWINE OP. Brandywine OP hereby indemnifies
and holds Prentiss harmless from and against any and all claims, costs,
penalties, damages, losses, liabilities and expenses (including reasonable
attorneys' fees) that may at any time be incurred by Prentiss, whether incurred
before or after Closing, as a result of any inaccuracy or breach by Brandywine
OP of any of its representations, warranties, covenants or obligations set forth
herein or in any other document delivered by Brandywine OP pursuant hereto
except for any breach or inaccuracy of any representation or warranty as to
which Brandywine OP has given Prentiss written notice prior to Closing of the
untruth or inaccuracy or of which Prentiss otherwise had actual knowledge prior
to the Closing and nevertheless elected to consummate the Closing. The
provisions of this Section shall survive the Closing of the transaction
contemplated hereby for the period described in SECTION 10.11 hereof.

     9.5   DEFAULT BY BRANDYWINE OP/FAILURE OF CONDITIONS PRECEDENT. If any
condition set forth herein for the benefit of Prentiss (other than a default by
Brandywine OP) cannot or will not be satisfied prior to Closing, and if
Brandywine OP fails to satisfy that condition within ten (10) business days
after notice thereof from Prentiss (or such other time period as may be
explicitly provided for herein), Prentiss may, at its option, elect either (a)
to terminate this Agreement in which event the Deposit shall be promptly
returned to Brandywine OP and the parties hereto shall be released from all
further obligations hereunder except those which expressly survive a termination
of this Agreement, or (b) to waive its right to terminate, and instead, to
proceed to Closing. If, prior to Closing, Brandywine OP defaults in performing
any of its obligations under this Agreement (including its obligation to
purchase the Property), and Brandywine OP fails to cure any such default within
ten (10) business days after notice thereof from Prentiss, then Prentiss' sole
remedy for such default shall be either (i) to terminate this Agreement and
retain the Deposit or (ii) to pursue the remedy of specific performance
compelling Brandywine OP to perform its obligations pursuant to the provisions
of this Agreement.

     9.6   COSTS AND ATTORNEYS' FEES. In the event of any litigation or dispute
between the parties arising out of or in any way connected with this Agreement,
resulting in any litigation, then the prevailing party in such litigation shall
be entitled to recover its costs of prosecuting and/or defending same,
including, without limitation, reasonable attorneys' fees at trial and all
appellate levels. The provisions of this Section shall survive the Closing of
the transaction contemplated hereby.

     9.7   LIMITATION OF LIABILITY. Notwithstanding anything herein to the
contrary, except in the case of fraud by either party, the liability of each
party hereto resulting from the breach or default by either party shall be
limited to actual damages incurred by the injured party and except

                                       40
<PAGE>

in the case of fraud by either party, the parties hereto hereby waive their
rights to recover from the other party consequential, punitive, exemplary, and
speculative damages. The provisions of this SECTION 9.7 shall survive the
Closing of the transaction contemplated hereby.

                                   ARTICLE X.
                            MISCELLANEOUS PROVISIONS

     10.1  COMPLETENESS; MODIFICATION. This Agreement constitutes the entire
agreement between the parties hereto with respect to the transactions
contemplated hereby and supersede all prior discussions, understandings,
agreements and negotiations between the parties hereto. This Agreement may be
modified only by a written instrument duly executed by the parties hereto. Any
waiver of rights under this Agreement shall be effective only if in writing and
duly executed and delivered by the party against whom such waiver is asserted.

     10.2  ASSIGNMENTS. Brandywine OP may assign its rights hereunder without
the consent of Prentiss to any affiliate of Brandywine OP, in which event,
except as otherwise specified herein, such assignee shall be the "BRANDYWINE OP"
hereunder; however, any such assignment shall not relieve the original
Brandywine OP of its obligations under this Agreement, including specifically
the obligation to close the purchase of the Property in accordance with this
Agreement as though there were no assignment.

     10.3  SUCCESSORS AND ASSIGNS. This Agreement shall bind and inure to the
benefit of the parties hereto and their respective successors and assigns.

     10.4  DAYS. If any action is required to be performed, or if any notice,
consent or other communication is given, on a day that is a Saturday or Sunday
or a legal holiday in the jurisdiction in which the action is required to be
performed or in which is located the intended recipient of such notice, consent
or other communication, such performance shall be deemed to be required, and
such notice, consent or other communication shall be deemed to be given, on the
first business day following such Saturday, Sunday or legal holiday. Unless
otherwise specified herein, all references herein to a "DAY" or "DAYS" shall
refer to calendar days and not business days.

     10.5  GOVERNING LAW. This Agreement and all documents referred to herein
shall be governed by and construed and interpreted in accordance with the laws
of the State of Delaware.

     10.6  COUNTERPARTS. To facilitate execution, this Agreement may be executed
in as many counterparts as may be required. It shall not be necessary that the
signature on behalf of both parties hereto appear on each counterpart hereof.
All counterparts hereof shall collectively constitute a single agreement.

     10.7  SEVERABILITY. If any term, covenant or condition of this Agreement,
or the application thereof to any person or circumstance, shall to any extent be
invalid or unenforceable, the remainder of this Agreement, or the application of
such term, covenant or condition to other persons or circumstances, shall not be
affected thereby, and each term, covenant or condition of this Agreement shall
be valid and enforceable to the fullest extent permitted by law.

                                       41
<PAGE>

     10.8  NOTICES. All notices, requests, demands and other communications
hereunder shall be in writing and shall be delivered by hand, transmitted by
facsimile transmission, sent prepaid by Federal Express (or a comparable
overnight delivery service) or sent by the United States mail, certified,
postage prepaid, return receipt requested, at the addresses and with such copies
as designated below. Any notice, request, demand or other communication
delivered or sent in the manner aforesaid shall be deemed given or made (as the
case may be) when actually delivered to the intended recipient.

     If to Brandywine OP: Brandywine Realty Trust
                          14 Campus Boulevard, Suite 100
                          Newtown Square, PA  19073-3780
                          Attn: Brad A. Molotsky, General Counsel
                          Fax No.: 610-325-4628

     If to Prentiss
      and/or PPL:         Prentiss Properties Acquisition Partners, L.P.
                          3860 West Northwest Highway, Suite 400
                          Dallas, Texas  75220
                          Attn.: J. Kevan Dilbeck, General Counsel
                          Fax No.: (214) 350-2409

     With a copy to:      Akin, Gump, Strauss, Hauer & Feld, L.L.P.
                          1700 Pacific Avenue, Suite 4100
                          Dallas, Texas 75201-4675
                          Attn.: Randall M. Ratner, P.C.
                          Fax No.: (214) 969-4343

     If to Escrow Agent:  Chicago Title Insurance Company
                          2001 Bryan Street, Suite 1700
                          Dallas, Texas 75201
                          Attn.: Ellen Schwab
                          Fax No.: (214) 965-1629

or to such other address as the intended recipient may have specified in a
notice to the other party. Any party hereto may change its address or designate
different or other persons or entities to receive copies by notifying the other
party and Escrow Agent in a manner described in this Section.

     10.9  ESCROW AGENT. Escrow Agent referred to in the definition thereof
contained in SECTION 1.1 hereof has agreed to act as such for the convenience of
the parties without fee or other charges for such services as Escrow Agent.
Escrow Agent shall not be liable: (a) to any of the parties for any act or
omission to act except for its own willful misconduct; (b) for any legal effect,
insufficiency, or undesirability of any instrument deposited with or delivered
by Escrow Agent or exchanged by the parties hereunder, whether or not Escrow
Agent prepared such instrument; (c) for any loss or impairment of funds that
have been deposited in escrow while those funds are in the course of collection,
or while those funds are on deposit in a financial institution, if such loss or
impairment results from the failure, insolvency or suspension of a

                                       42
<PAGE>

financial institution; (d) for the expiration of any time limit or other
consequence of delay, unless a properly executed written instruction, accepted
by Escrow Agent, has instructed Escrow Agent to comply with said time limit; or
(e) for the default, error, action or omission of either party to the escrow.
Escrow Agent, in its capacity as escrow agent, shall be entitled to rely on any
document or paper received by it, believed by such Escrow Agent, in good faith,
to be bona fide and genuine. In the event of any dispute as to the disposition
of the Deposit or any other monies held in escrow, or of any documents held in
escrow, Escrow Agent may, if such Escrow Agent so elects, interplead the matter
by filing an interpleader action in a court of general jurisdiction in the
county or circuit where the Real Property is located (to the jurisdiction of
which both parties do hereby consent), and pay into the registry of the court
the Deposit, or deposit any such documents with respect to which there is a
dispute in the Registry of such court, whereupon such Escrow Agent shall be
relieved and released from any further liability as Escrow Agent hereunder.
Escrow Agent shall not be liable for Escrow Agent's compliance with any legal
process, subpoena, writ, order, judgment and decree of any court, whether issued
with or without jurisdiction, and whether or not subsequently vacated, modified,
set aside or reversed.

     10.10 INCORPORATION BY REFERENCE. All of the exhibits attached hereto are
by this reference incorporated herein and made a part hereof.

     10.11 SURVIVAL. All of the representations, warranties, covenants and
agreements of Prentiss, PPL and Brandywine OP made in, or pursuant to, this
Agreement shall survive Closing through the period ending twelve (12) months
thereafter and shall not merge into any document or instrument executed and
delivered in connection herewith; provided, however, the covenants in SECTIONS
2.4(b), 6.6 AND 7.6 shall survive for the time periods described in such
SECTIONS, and the indemnities in this Agreement and the covenants in SECTIONS
6.9 AND 7.8 shall have an unlimited survival period. In the event a claim for
indemnity is asserted in good faith prior to the expiration of the applicable
survival period, the claim may be asserted and the indemnity shall continue
notwithstanding the expiration of the survival period.

     10.12 FURTHER ASSURANCES. Prentiss and Brandywine OP each covenant and
agree to sign, execute and deliver, or cause to be signed, executed and
delivered, and to do or make, or cause to be done or made, upon the written
request of the other party, any and all agreements, instruments, papers, deeds,
acts or things, supplemental, confirmatory or otherwise, as may be reasonably
required by either party hereto for the purpose of or in connection with
consummating the transactions described herein. Prentiss agrees to promptly
correct any defect, error or omission which may be discovered in the contents of
this Agreement or in any of the Exhibits or Schedules hereto.

     10.13 NO PARTNERSHIP. This Agreement does not and shall not be construed to
create a partnership, joint venture or any other relationship between the
parties hereto except the relationship of Prentiss and Brandywine OP
specifically established hereby.

     10.14 TIME OF ESSENCE. Time is of the essence with respect to every
provision hereof.

     10.15 SIGNATORY EXCULPATION. The signatory(ies) for Prentiss, PPL and
Brandywine OP are executing this Agreement in his/their capacity as
representative of Prentiss, PPL and Brandywine OP, respectively, and not
individually and, therefore, shall have no personal or

                                       43
<PAGE>

individual liability of any kind in connection with this Agreement and the
transactions contemplated by it. No recourse shall be had for any obligation of
Prentiss, PPL or Brandywine OP under this Agreement or under any document
executed in connection herewith or pursuant hereto, or for any claim based
thereon or otherwise in respect thereof, against any past, present or future
trustee, shareholder, officer, partner or employee of Brandywine Realty Trust,
Prentiss Properties Trust, Prentiss, PPL or Brandywine OP, whether by virtue of
any statute or rule of law, or by the enforcement of any assessment or penalty
or otherwise, all such liability being expressly waived and released by the
parties hereto and all parties claiming by, through or under them.

     10.16 RULES OF CONSTRUCTION. The following rules shall apply to the
construction and interpretation of this Agreement:

           (a) Singular words shall connote the plural number as well as the
singular and vice versa, and the masculine shall include the feminine and the
neuter.

           (b) All references herein to particular articles, sections,
subsections, clauses or exhibits are references to articles, sections,
subsections, clauses or exhibits of this Agreement.

           (c) The table of contents and headings contained herein are solely
for convenience of reference and shall not constitute a part of this Agreement
nor shall they affect its meaning, construction or effect.

           (d) Each party hereto and its counsel have reviewed and revised (or
requested revisions of) this Agreement and have participated in the preparation
of this Agreement, and therefore any usual rules of construction requiring that
ambiguities are to be resolved against a particular party shall not be
applicable in the construction and interpretation of this Agreement or any
exhibits hereto.

           (e) As used herein, the term or phrases "EFFECTIVE DATE," "DATE OF
THIS AGREEMENT" or "DATE HEREOF" shall mean the first date Escrow Agent is in
receipt of this Agreement executed by Prentiss and Brandywine OP.

     10.17 SEC REPORTING (8-K) REQUIREMENTS. For the period of time commencing
on the date hereof and continuing through the second anniversary of the Closing
Date, and without limitation of other document production otherwise required of
Prentiss hereunder, Prentiss shall, from time to time, upon reasonable advance
written notice from Brandywine OP, provide Brandywine OP and its
representatives, with access to all financial and other information pertaining
to the period of the respective Partnership's ownership and operation of the
Property, which information is relevant and reasonably necessary, in the opinion
of outside, third party accountants (the "ACCOUNTANTS") for Brandywine OP, to
enable Brandywine OP and its Accountants to prepare financial statements in
compliance with any or all of (a) Rule 3-05 or 3-14 of Regulation S-X of the
Securities and Exchange Commission (the "COMMISSION"), as applicable; (b) any
other rule issued by the Commission and applicable to Brandywine OP or
Brandywine Realty Trust ("BRANDYWINE"); and (c) any registration statement,
report or disclosure statement filed with the Commission by Brandywine; and a
representation letter, signed by the individual(s) responsible for Prentiss'
financial reporting, as prescribed by generally accepted

                                       44
<PAGE>

auditing standards promulgated by the Auditing Standards Division of the
American Institute of Certified Public Accountants, which representation letter
may be required by the Accountants in order to render an opinion concerning
Brandywine OP's or Brandywine's financial statements.

                                       45
<PAGE>

     IN WITNESS WHEREOF, Prentiss and Brandywine OP have caused this Agreement
to be executed in their names by their respective duly authorized
representatives.

                               BRANDYWINE OP:

                               BRANDYWINE  OPERATING  PARTNERSHIP,
                               L.P., a Delaware  limited partnership

                               By: Brandywine Realty Trust, its general partner

                                   By:  /s/ GERARD H. SWEENEY
                                        ---------------------
                                            Gerard H. Sweeney
                                   Name:    Gerard H. Sweeney
                                   Title:   President & CEO

                                   Date of Execution: March 14, 2001

                               PRENTISS:

                               PRENTISS PROPERTIES ACQUISITION
                               PARTNERS, L.P., a Delaware limited partnership

                               By: Prentiss Properties I, Inc., a Delaware
                                   corporation, its general partner

                                   By:  /s/ GERARD H. SWEENEY
                                        ---------------------
                                            Gerard H. Sweeney
                                   Name:    Gerard H. Sweeney
                                   Title:   President & CEO

                                   Date of Execution: March 14, 2001

                               PPL:

                               PRENTISS PROPERTIES LIMITED, INC., a
                               Delaware corporation

                               By:  /s/ THOMAS F. AUGUST
                                    --------------------
                                        Thomas F. August
                               Name:    Thomas F. August
                               Title:   President & CEO

                               Date of Execution: March 14, 2001

                                       46
<PAGE>

                             RECEIPT OF ESCROW AGENT

     Chicago Title Insurance Company, as Escrow Agent, acknowledges receipt of
the sum of $100,050.00 by check or by wire transfer, from Brandywine OP as
described in SECTION 2.3 of the foregoing Agreement of Purchase and Sale, said
check or wire transfer to be held pursuant to the terms and provisions of said
Agreement.

     DATED this _____ day of __________, 2001.

                               CHICAGO TITLE INSURANCE COMPANY

                               By:
                                     ----------------------------
                               Name:
                                     ----------------------------
                               Title:
                                     ----------------------------

                                       47

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