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                                                                   Exhibit 10.23

                         AGREEMENT OF SALE AND PURCHASE

     THIS AGREEMENT OF SALE AND PURCHASE ("AGREEMENT") is made this 6th day of
June, 2002, to be effective as of the Effective Date, by and between MACK-CALI
TEXAS PROPERTY L.P., a limited partnership organized under the laws of the State
of Texas having an address c/o Mack-Cali Realty Corporation, 11 Commerce Drive,
Cranford, New Jersey 07016 ("SELLER"), and PARKWAY PROPERTIES LP, a limited
partnership organized under the laws of the State of Delaware having an address
at One Jackson Place, 188 East Capitol Street, Suite 1000, Jackson, Mississippi
39201-2195 ("PURCHASER").

     In consideration of the mutual promises, covenants, and agreements set
forth herein, and other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Seller and Purchaser agree as
follows:

                                    ARTICLE I
                                   DEFINITIONS

     SECTION 1.1    DEFINITIONS. For purposes of this Agreement, the following
capitalized terms have the meanings set forth in this Section 1.1:

     "ASSIGNMENT" has the meaning ascribed to such term in Section 10.3(d) and
shall be in the form attached hereto as EXHIBIT A.

     "ASSIGNMENT OF LEASES" has the meaning ascribed to such term in Section
10.3(c) and shall be in the form attached hereto as EXHIBIT B.

     "AUTHORITIES" means the various federal, state and local governmental and
quasi-governmental bodies or agencies having jurisdiction over the Real Property
and Improvements, or any portion thereof.

     "BILL OF SALE" has the meaning ascribed to such term in Section 10.3(b) and
shall be in the form attached hereto as EXHIBIT C.

     "BROKER" has the meaning ascribed to such term in Section 16.1.

     "BUSINESS DAY" means any day other than a Saturday, Sunday or a day on
which national banking associations are authorized or required to close.

     "CERTIFICATE AS TO FOREIGN STATUS" has the meaning ascribed to such term in
Section 10.3(g) and shall be in the form attached as EXHIBIT I.

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     "CERTIFYING PERSON" has the meaning ascribed to such term in Section
4.3(a).

     "CLOSING" means the consummation of the purchase and sale of the Property
contemplated by this Agreement, as provided for in Article X.

     "CLOSING DATE" means the date on which the Closing of the transaction
contemplated hereby actually occurs.

     "CLOSING STATEMENT" has the meaning ascribed to such term in Section
10.4(a).

     "CLOSING SURVIVING OBLIGATIONS" means the rights, liabilities and
obligations set forth in Sections 3.2, 4.3, 5.3, 5.4, 7.4, 8.2, 8.3 (including
the references to Sections 7.1, 7.2 and 8.1 in Section 8.3), 10.4, 10.6, 11.1,
11.2, 16.1, 18.1, 18.4 and 18.10 and Article XIV, and any other provisions which
pursuant to their terms survive the Closing hereunder.

     "CODE" has the meaning ascribed to such term in Section 4.3.

     "CONDITIONS PRECEDENT CURE PERIOD" has the meaning ascribed to such term in
Section 9.2(b).

     "CONFIDENTIALITY AGREEMENT" means that certain Confidentiality Agreement
dated January 29, 2002 between Purchaser or an affiliate of Purchaser and
Seller.

     "CONSTRUCTION CONTRACT ESTOPPEL" has the meaning ascribed to such term in
Section 3.2.

     "CONSTRUCTION CONTRACTS" means all contracts to which Seller is a party for
the current construction of Tenant improvements or capital repairs, replacements
or upgrades affecting the Property, which are set forth on EXHIBIT O attached
hereto, together with all supplements, amendments and modifications thereof, and
any new such agreements entered into after the Effective Date, to the extent
permitted by Section 7.1.

     "DEED" has the meaning ascribed to such term in Section 10.3(a).

     "DELINQUENT RENTAL" has the meaning ascribed to such term in Section
10.4(b).

     "DOCUMENTS" has the meaning ascribed to such term in Section 5.2(a).

     "EARNEST MONEY DEPOSIT" has the meaning ascribed to such term in Section
4.1.

     "EAT" has the meaning ascribed to such term in Section 10.7.

     "EFFECTIVE DATE" means May 31, 2002.

     "EMPLOYEE NOTICE" has the meaning ascribed to such term in Section
9.2(a)(v).

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     "ENVIRONMENTAL LAWS" means each and every federal, state, county and
municipal statute, ordinance, rule, regulation, code, order, requirement,
directive, binding written interpretation and binding written policy pertaining
to Hazardous Substances issued by any Authorities and in effect as of the date
of this Agreement with respect to or which otherwise pertains to or affects the
Real Property or the Improvements, or any portion thereof, the use, ownership,
occupancy or operation of the Real Property or the Improvements, or any portion
thereof, or Purchaser, and as same have been amended, modified or supplemented
from time to time prior to the Effective Date, including but not limited to the
Comprehensive Environmental Response, Compensation and Liability Act of 1980 (42
U.S.C. Section 9601 et seq.), the Hazardous Substances Transportation Act (49
U.S.C. Section 1802 et seq.), the Resource Conservation and Recovery Act (42
U.S.C. Section 6901 et seq.), as amended by the Hazardous and Solid Wastes
Amendments of 1984, the Water Pollution Control Act (33 U.S.C. Section 1251 et
seq.), the Safe Drinking Water Act (42 U.S.C. Section 300f et seq.), the Clean
Water Act (33 U.S.C. Section 1321 et seq.), the Clean Air Act (42 U.S.C. Section
7401 et seq.), the Solid Waste Disposal Act (42 U.S.C. Section 6901 et seq.),
the Toxic Substances Control Act (15 U.S.C. Section 2601 et seq.), the Emergency
Planning and Community Right-to-Know Act of 1986 (42 U.S.C. Section 11001 et
seq.), the Radon Gas and Indoor Air Quality Research Act of 1986 (42 U.S.C.
Section 7401 et seq.), the National Environmental Policy Act (42 U.S.C. Section
4321 et seq.), the Superfund Amendment Reauthorization Act of 1986 (42 U.S.C.
Section 9601 et seq.), the Occupational Safety and Health Act (29 U.S.C. Section
651 et seq.) (collectively, the "ENVIRONMENTAL STATUTES"), and any and all rules
and regulations which have become effective prior to the date of this Agreement
under any and all of the Environmental Statutes.

     "ENVIRONMENTAL REPORTS" means all existing environmental reports and
studies of the Real Property that have been prepared for Seller as listed and
described on EXHIBIT L attached hereto.

     "ESCROW AGENT" means Lawyers Title Insurance Corporation, having an address
at 655 Third Avenue, 11th Floor, New York, New York 10017.

     "ESCROWED FUNDS" has the meaning ascribed to such term in Section 17.1(b).

     "ESTOPPEL CERTIFICATE" has the meaning ascribed to such term in Section
7.2(a).

     "EVALUATION PERIOD" has the meaning ascribed to such term in Section 5.1.

     "EXISTING SURVEY" means Seller's existing survey of the Property last
revised April 4, 2001, prepared by International Land Services, Inc.

     "EXTENDED CLOSING DATE" has the meaning ascribed to such term in Section
9.2(b).

     "FORM SELLER ESTOPPEL CERTIFICATE" has the meaning ascribed to such term in
Section 7.2(b).

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     "FORM TENANT ESTOPPEL CERTIFICATE" has the meaning ascribed to such term in
Section 7.2(a).

     "GOVERNMENTAL REGULATIONS" means all statutes, ordinances, rules and
regulations of the Authorities applicable to Seller or the use or operation of
the Real Property or the Improvements or any portion thereof.

     "HAZARDOUS SUBSTANCES" means (a) asbestos, radon gas and urea formaldehyde
foam insulation, (b) any solid, liquid, gaseous or thermal contaminant,
including smoke vapor, soot, fumes, acids, alkalis, chemicals, petroleum
products or byproducts, polychlorinated biphenyls, phosphates, lead or other
heavy metals and chlorine, (c) any solid or liquid waste (including, without
limitation, hazardous waste), hazardous air pollutant, hazardous substance,
hazardous chemical substance and mixture, toxic substance, pollutant, pollution,
regulated substance and contaminant, and (d) any other chemical, material or
substance, the use or presence of which, or exposure to the use or presence of
which, is prohibited, limited or regulated by any Environmental Laws.

     "IMPROVEMENTS" means all buildings, structures, fixtures, HVAC systems
owned by Seller, parking areas and other improvements located on the Real
Property.

     "LEASE SCHEDULE" means the schedule of Leases attached as EXHIBIT F, as
such schedule may be updated as permitted by this Agreement.

     "LEASES" means all of the leases and other agreements entered into by
Seller (or a predecessor-in-interest), as landlord, and any tenant or user of
all or any portion of the Property prior to the Effective Date with respect to
the use and occupancy of any portion of the Property, which are set forth on
EXHIBIT F attached hereto, together with all amendments, renewals and
modifications thereof, if any, and all guaranties thereof, if any, entered into
as of the Effective Date, together with all new leases, amendments, renewals and
modifications of existing leases and lease guaranties entered into after the
Effective Date in accordance with the terms of this Agreement.

     "LEASING COMMISSION AGREEMENTS" means all leasing commission agreements
that affect the Property as of the Effective Date, which are set forth on
EXHIBIT J attached hereto, together with any new such agreements entered into
after the Effective Date, to the extent permitted by Section 7.1.

     "LICENSEE PARTIES" has the meaning ascribed to such term in Section 5.1.

     "LICENSES AND PERMITS" means, collectively, all of Seller's right, title
and interest, to the extent assignable, in and to licenses, permits,
certificates of occupancy, approvals, dedications, subdivision maps and
entitlements now or hereafter issued, approved or granted by the Authorities
exclusively in connection with the Real Property and the Improvements, together
with all renewals and modifications thereof.

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     "LLCs" has the meaning ascribed to such term in Section 10.7.

     "MAJOR TENANT" means any Tenant leasing in excess of 5,000 square feet of
space in the aggregate at the Property as listed on EXHIBIT P attached hereto.

     "NEW OBJECTION DATE" has the meaning ascribed to such term in Section
6.2(a).

     "OPERATING EXPENSES" has the meaning ascribed to such term in Section
10.4(c).

     "OPERATING STATEMENTS" means operating statements for the Property for
calendar years 2000 and 2001 and for each calendar month of 2002 through the
month ending April 30, 2002.

     "ORIGINAL AGREEMENT" has the meaning ascribed to such term in Section 18.8.

     "ORIGINAL OBJECTION DATE" has the meaning ascribed to such term in Section
6.2(a).

     "OTHER TENANTS" has the meaning ascribed to such term in Section 7.2(a).

     "PARTIAL CERTIFICATE" has the meaning ascribed to such term in Section
7.2(b).

     "PERMITTED EXCEPTIONS" has the meaning ascribed to such term in Section
6.2(a).

     "PERMITTED OUTSIDE PARTIES" has the meaning ascribed to such term in
Section 5.2(b).

     "PERSONAL PROPERTY" means all equipment, appliances, tools, supplies, life
safety support systems, canopies, planters, landscaping, building materials,
inventory, machinery, artwork, promotional materials, furnishings and other
tangible personal property attached to, appurtenant to, located in and used
exclusively in connection with the ownership or operation of the Improvements
and situated at the Property at the time of Closing. Notwithstanding the
preceding sentence, "Personal Property" shall not include (a) any proprietary or
confidential materials or any materials that contain the logo of Seller or of
Mack-Cali Realty Corporation, except for any promotional materials (which shall
be subject to Section 18.1), (b) any property that serves or is used in
connection with any property other than the Property, (c) any property owned by
tenants or others or (d) any property leased by Seller.

     "PROJECTS" means, collectively, all of the Property, together with the 1717
St. James Project and the Town & Country Project.

     "PROPERTY" has the meaning ascribed to such term in Section 2.1.

     "PRORATION ITEMS" has the meaning ascribed to such term in Section 10.4(a).

     "PRORATION TIME" has the meaning ascribed to such term in Section 10.4(a).

     "PURCHASE PRICE" has the meaning ascribed to such term in Section 3.1.

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     "PURCHASER'S AFFILIATES" means any past, present or future: (i)
shareholder, partner, member, manager or owner of Purchaser that has a
controlling interest in Purchaser; (ii) general partner of Purchaser; (iii)
entity in which Purchaser has or had any controlling interest and entity in
which any past, present or future shareholder, partner, member, manager or owner
of Purchaser has or had a controlling interest; (iv) entity that, directly or
indirectly, controls, is controlled by or is under common control with Purchaser
and (v) the heirs, executors, administrators, personal or legal representatives,
successors and assigns of any or all of the foregoing.

     "PURCHASER'S INFORMATION" has the meaning ascribed to such term in Section
5.3(c).

     "QI" has the meaning ascribed to such term in Section 10.7.

     "REAL PROPERTY" means that certain parcel of real property located at 5300
Memorial Drive, Houston, Texas, as more particularly described on the legal
description attached hereto and made a part hereof as EXHIBIT D, together with
all of Seller's right, title and interest, if any, in and to the appurtenances
pertaining thereto, including but not limited to Seller's right, title and
interest in and to the adjacent streets, alleys and right-of-ways, and any
easement rights, air rights, subsurface development rights and water rights.

     "RENTAL" has the meaning ascribed to such term in Section 10.4(b), and same
are "Delinquent" in accordance with the meaning ascribed to such term in Section
10.4(b).

     "REVENUE PROCEDURE" has the meaning ascribed to such term in Section 10.7.

     "SCHEDULED CLOSING DATE" means June 4, 2002 or such earlier or later date
to which Purchaser and Seller may hereafter agree in writing and subject to
extension as expressly permitted by this Agreement.

     "SECOND CONDITIONS PRECEDENT CURE PERIOD" has the meaning ascribed to such
term in Section 9.2(b).

     "SECOND EXTENDED CLOSING DATE" has the meaning ascribed to such term in
Section 9.2(b).

     "SECTION 1031 EXCHANGE" has the meaning ascribed to such term in Section
10.7.

     "SECURITY DEPOSITS" means all security deposits and other deposits paid to
Seller, as landlord (and not applied in the event of a Tenant default), to the
extent attributable to the Property or any portion of the Property (together
with any interest which has accrued thereon, but only to the extent such
interest has accrued for the account of the Tenant), which are set forth on
EXHIBIT N attached hereto.

     "SELLER ESTOPPEL CERTIFICATE" has the meaning ascribed to such term in
Section 7.2(b).

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     "SELLER'S AFFILIATES" means any past, present or future: (i) shareholder,
partner, member, manager or owner of Seller; (ii) entity in which Seller or any
past, present or future shareholder, partner, member, manager or owner of Seller
has or had an interest; (iii) entity that, directly or indirectly, controls, is
controlled by or is under common control with Seller and (iv) the heirs,
executors, administrators, personal or legal representatives, successors and
assigns of any or all of the foregoing.

     "SELLER'S KNOWLEDGE" means the actual knowledge possessed by Jeff Kennemer,
Senior Director of Property Management of M-C Texas Management L.P., James
Clabby, Senior Vice President, Western Region, of M-C Texas Management L.P.,
Belinda Wolfe, property manager of the Property, Terri Torregrossa, leasing
director of the Property, and Theresa Levers, Supervisor of Property Accounting
for the Property, without further inquiry. Notwithstanding anything contained
herein to the contrary, none of the foregoing individuals shall have any
personal liability or obligation whatsoever with respect to any of the matters
set forth in this Agreement or any of Seller's representations and/or warranties
herein being or becoming untrue, inaccurate or incomplete in any respect.

     "SEPARATION AGREEMENTS" means those agreements with Seller's current
employees relating to stay-on bonuses and separation pay.

     "SERVICE CONTRACTS" means all service agreements, maintenance contracts,
equipment leasing agreements, project management agreements, warranties,
guarantees, bonds, open purchase orders and other contracts for the provision of
labor, services, materials or supplies relating solely to the Real Property,
Improvements or Personal Property and under which Seller is currently paying for
services rendered in connection with the Property, as listed and described on
EXHIBIT E attached hereto, together with all renewals, supplements, amendments
and modifications thereof, and any new such agreements entered into after the
Effective Date, to the extent permitted by Section 7.1. Notwithstanding the
foregoing, the definition of Service Contracts does not include the Spectrasite
Agreements, the Construction Contracts, the Leasing Commission Agreements or the
Separation Agreements.

     "1717 ST. JAMES AGREEMENT" means that certain Agreement of Sale and
Purchase, of even date herewith, between Seller and Purchaser pertaining to the
sale of the property located at 1717 St. James Place, Houston, Texas.

     "1717 ST. JAMES PROJECT" means all of the property described as "Property"
under Section 2.1 of the St. James Agreement.

     "SIGNIFICANT PORTION" means, for purposes of the casualty provisions set
forth in Article XI hereof, damage by fire or other casualty to the Real
Property and the Improvements or a portion thereof, the cost of which to repair
would exceed One Million Dollars ($1,000,000).

     "SPECTRASITE AGREEMENTS" means that certain Agreement for the management of
rooftop transmitting sites dated July 6, 1998, between Mack-Cali Realty
Corporation on behalf of Seller and Spectrasite Building Group, Inc.
("SPECTRASITE"), as successor-in-interest to Apex Site

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Management, Inc., and that certain Agreement for the management of
telecommunications access sites dated October 24, 2001, between Mack-Cali Realty
Corporation on behalf of Seller and Spectrasite.

     "SURVEY OBJECTION" has the meaning ascribed to such term in Section 6.2.

     "TENANT NOTICE LETTERS" has the meaning ascribed to such term in Section
10.2(e), and are to be delivered by Purchaser to Tenants pursuant to Section
10.6.

     "TENANTS" means the tenants or users of all or any portion of the Property
claiming rights pursuant to Leases.

     "TERMINATION SURVIVING OBLIGATIONS" means the rights, liabilities and
obligations set forth in Sections 5.2, 5.3, 5.4, 12.1, 16.1, 18.4 and 18.10, and
Articles XIII and XIV, and any other provisions which pursuant to their terms
survive any termination of this Agreement.

     "TITLE COMMITMENT" has the meaning ascribed to such term in Section 6.2(a).

     "TITLE COMPANY" means Lawyers Title Insurance Corporation, having an
address at 655 Third Avenue, 11th Floor, New York, New York 10017.

     "TITLE DEFECT" has the meaning ascribed to such term in Section 6.3(a).

     "TITLE OBJECTIONS" has the meaning ascribed to such term in Section 6.2(a).

     "TITLE POLICY" has the meaning ascribed to such term in Section 6.2(a).

     "TOWN & COUNTRY AGREEMENT" means that certain Agreement of Sale and
Purchase, of even date herewith, between Seller and Purchaser pertaining to the
sale of the property located at 10497 Town & Country Way, Houston, Texas.

     "TOWN & COUNTRY PROJECT" means all of the property described as "Property"
under Section 2.1 of the Town & Country Agreement.

     "TRADE NAMES" means any trade names used by Seller exclusively in
connection with the ownership, use or operation of the Real Property or the
Improvements, but specifically excluding any trade names that include the words
"Mack-Cali" or "M-C" or any other trade names owned by Mack-Cali Realty
Corporation, M-C Texas Property Management L.P. or any of their respective
affiliates.

     "UPDATED SURVEY" has the meaning ascribed to such term in Section 6.1.

     SECTION 1.2    REFERENCES: EXHIBITS AND SCHEDULES. Except as otherwise
specifically indicated, all references in this Agreement to Articles or Sections
refer to Articles or Sections of this Agreement, and all references to Exhibits
or Schedules refer to Exhibits or Schedules attached hereto, all of which
Exhibits and Schedules are incorporated into, and made a part of,

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this Agreement by reference. The words "herein," "hereof," "hereinafter" and
words and phrases of similar import refer to this Agreement as a whole and not
to any particular Section or Article.

                                   ARTICLE II
                         AGREEMENT OF PURCHASE AND SALE

     SECTION 2.1    AGREEMENT. Seller hereby agrees to sell, convey and assign
to Purchaser, and Purchaser hereby agrees to purchase and accept from Seller, on
the Closing Date and subject to the terms and conditions of this Agreement, all
of Seller's right, title and interest in and to the following (collectively, the
"PROPERTY"):

            (a)     the Real Property;

            (b)     the Improvements;

            (c)     the Personal Property;

            (d)     the Leases and, subject to the terms of the respective
applicable Leases, the Security Deposits;

            (e)     to the extent assignable, the Licenses and Permits;

            (f)     to the extent assignable, the Construction Contracts;

            (g)     subject to Section 3.2, the Spectrasite Agreements; and

            (h)     to the extent assignable or transferable, in and to all
other intangible rights, titles, interests, privileges and appurtenances
(including, without limitation, guarantees, warranties and Trade Names) owned by
Seller and related to or used exclusively in connection with the ownership, use
or operation of the Real Property or the Improvements, but specifically
excluding any proprietary or confidential materials and any property that serves
or is used in connection with any property other than the Property.

     SECTION 2.2    INDIVISIBLE ECONOMIC PACKAGE. Purchaser has no right to
purchase, and Seller has no obligation to sell, less than all of the Property,
it being the express agreement and understanding of Purchaser and Seller that,
as a material inducement to Seller and Purchaser to enter into this Agreement,
Purchaser has agreed to purchase, and Seller has agreed to sell, all of the
Property, subject to and in accordance with the terms and conditions hereof.

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                                   ARTICLE III
                                  CONSIDERATION

     SECTION 3.1    PURCHASE PRICE. The purchase price for the Property (the
"PURCHASE PRICE") shall be Twelve Million Three Hundred Sixty-Six Thousand Three
Hundred Ninety-Two Dollars ($12,366,392) in lawful currency of the United States
of America, payable as provided in Section 3.3. No portion of the Purchase Price
shall be allocated to the Personal Property.

     SECTION 3.2    ASSUMPTION OF OBLIGATIONS. As additional consideration for
the purchase and sale of the Property, at Closing Purchaser will assume all of
the covenants and obligations of Seller pursuant to the Leases, Spectrasite
Agreements, Construction Contracts and Licenses and Permits that are to be
performed subsequent to the Closing Date, provided that certain credits will be
provided to Purchaser at Closing for post-Closing obligations as expressly set
forth elsewhere in this Agreement. As a condition to Purchaser assuming the
Construction Contracts, Seller will use commercially reasonable efforts to
obtain estoppels (each, a "CONSTRUCTION CONTRACT ESTOPPEL") from the contractors
thereunder, on the standard AIA estoppel form, verifying that the Construction
Contracts are in full force in effect, that no material event of default, or
event that, with the giving of notice or passage of time could become a material
event of default, exists under any Construction Contract, the balance due under
each Construction Contract and that the balance due is sufficient to complete
the work contemplated by such Construction Contract, provided that if, after
using commercially reasonable efforts to do so, Seller is unable to obtain one
or more of the Construction Contract Estoppels, Seller will provide the
representation and warranty set forth in the second sentence of Section 10.3(i)
with respect to each Construction Contract for which a Construction Contract
Estoppel was not obtained, and so long as such representation and warranty is
provided by Seller, the failure to provide a Construction Contract Estoppel will
not constitute a failure of a condition precedent under this Agreement. Seller
agrees to cooperate with Purchaser in working with the vendors under the Service
Contracts so that the Service Contracts will be terminated as of the Closing
Date and Purchaser will enter into new contracts with such vendors as of the
Closing Date. In no event will Purchaser be obligated to assume any Service
Contract or Leasing Commission Agreement. Purchaser shall not be required to
assume the covenants and obligations of Seller under the Spectrasite Agreements
if prior to Closing Purchaser complies with the requirements of the letter dated
April 10, 2002 from Spectrasite to Mack-Cali Realty Corporation and Purchaser.
In the absence of the foregoing, at Closing Purchaser will assume the covenants
and obligations of Seller pursuant to the Spectrasite Agreements (to the extent
they affect the Property). Seller shall be liable for and shall satisfy all of
the obligations of Seller pursuant to the Service Contracts, Spectrasite
Agreements, Construction Contracts, Leasing Commission Agreements and the Leases
that are to be performed prior to Closing, except to the extent credit is given
to Purchaser at Closing (unless the document in question has been terminated as
of or prior to Closing or relates to the Service Contracts or Leasing Commission
Agreements) for the cost of any such obligations that Seller has not performed
prior to Closing (in which event, Purchaser shall assume such obligation except
for obligations under the Service Contracts and Leasing Commission Agreements).

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     SECTION 3.3    METHOD OF PAYMENT OF PURCHASE PRICE. No later than 1:00 p.m.
Eastern Time on the Closing Date, Purchaser shall pay to Seller the Purchase
Price (less the Earnest Money Deposit), together with all other costs and
amounts to be paid by Purchaser at the Closing pursuant to the terms of this
Agreement ("PURCHASER'S COSTS"), by Federal Reserve wire transfer of immediately
available funds to the account of Escrow Agent. Escrow Agent, following
authorization and instruction by the parties at Closing, shall (i) pay to Seller
by Federal Reserve wire transfer of immediately available funds to an account
designated by Seller, the Purchase Price, less any costs or other amounts to be
paid by Seller at Closing pursuant to the terms of this Agreement, (ii) pay to
the appropriate payees out of the proceeds of Closing payable to Seller all
costs and amounts to be paid by Seller at Closing pursuant to the terms of this
Agreement, and (iii) pay Purchaser's Costs to the appropriate payees at Closing
pursuant to the terms of this Agreement.

                                   ARTICLE IV
                              EARNEST MONEY DEPOSIT
                             AND ESCROW INSTRUCTIONS

     SECTION 4.1    THE EARNEST MONEY DEPOSIT AND INDEPENDENT CONTRACT
CONSIDERATION.

            (a)     Simultaneously with the execution and delivery of this
Agreement by Purchaser, Purchaser shall deposit with the Escrow Agent, by
Federal Reserve wire transfer of immediately available funds, the sum of One
Hundred Sixty Thousand Dollars ($160,000) as the initial earnest money deposit
on account of the Purchase Price (the "EARNEST MONEY DEPOSIT").

            (b)     In the event that Purchaser does not terminate this
Agreement prior to the expiration of the Evaluation Period as provided for in
Section 5.3(c), Purchaser shall, prior to the expiration of the Evaluation
Period, deposit with Escrow Agent, by wire transfer of immediately available
funds, the sum of Three Hundred Thousand Dollars ($300,000) as additional
earnest money on account of the Purchase Price, which additional earnest money
will, upon deposit with Escrow Agent, become part of the Earnest Money Deposit.

            (c)     Simultaneously with the execution and delivery of this
Agreement by Purchaser, Purchaser shall, in addition to the Earnest Money
Deposit, pay to Seller, by Federal Reserve wire transfer of immediately
available funds or by check payable to the order of Seller, One Hundred Dollars
($100.00) as independent consideration for Seller's execution of this Agreement.

     SECTION 4.2    ESCROW INSTRUCTIONS. The Earnest Money Deposit shall be held
in escrow by the Escrow Agent in an interest-bearing account, in accordance with
the provisions of Article XVII. In the event this Agreement is not terminated by
Purchaser pursuant to the terms hereof by the end of the Evaluation Period in
accordance with the provisions of Section 5.3(c) herein, the Earnest Money
Deposit and the interest earned thereon shall become non-refundable to
Purchaser, except as otherwise expressly provided in this Agreement. In the
event this

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Agreement is terminated by Purchaser prior to the expiration of the Evaluation
Period, the Earnest Money Deposit, together with all interest earned thereon,
shall be refunded to Purchaser.

     SECTION 4.3    DESIGNATION OF CERTIFYING PERSON. In order to assure
compliance with the requirements of Section 6045 of the Internal Revenue Code of
1986, as amended (the "CODE"), and any related reporting requirements of the
Code, the parties hereto agree as follows:

            (a)     The Escrow Agent agrees to assume all responsibilities for
information reporting required under Section 6045(e) of the Code, and Seller and
Purchaser hereby designate the Escrow Agent as the person to be responsible for
all information reporting under Section 6045(e) of the Code (the "CERTIFYING
PERSON").

            (b)     Seller and Purchaser each hereby agree:

                    (i)    to provide to the Certifying Person all information
            and certifications regarding such party, as reasonably requested by
            the Certifying Person or otherwise required to be provided by a
            party to the transaction described herein under Section 6045 of the
            Code; and

                    (ii)   to provide to the Certifying Person such party's
            taxpayer identification number and a statement (on Internal Revenue
            Service Form W-9 or an acceptable substitute form, or on any other
            form the applicable current or future Code sections and regulations
            might require and/or any form requested by the Certifying Person),
            signed under penalties of perjury, stating that the taxpayer
            identification number supplied by such party to the Certifying
            Person is correct.

                                    ARTICLE V
                             INSPECTION OF PROPERTY

     SECTION 5.1    EVALUATION PERIOD. For a period ending at 5:00 p.m. Eastern
Time on May 29, 2002 (the "EVALUATION PERIOD"), Purchaser and its authorized
agents and representatives (for purposes of this Article V, the "LICENSEE
PARTIES") shall have the right, subject to the right of any Tenants, to enter
upon the Real Property at all reasonable times during normal business hours to
perform an inspection of the Property. Purchaser will provide to Seller notice
of the intention of Purchaser or the other Licensee Parties to enter the Real
Property at least 24 hours (and no less than one (1) Business Day) prior to such
intended entry and specify the intended purpose therefor and the inspections and
examinations contemplated to be made and with whom any Licensee Party will
communicate. At Seller's option, Seller may be present for any such entry and
inspection. Purchaser shall not communicate with or contact any of the Tenants
without the prior consent of Seller, which consent shall not be unreasonably
withheld or delayed. Purchaser may communicate with or contact Authorities
regarding the Property without the prior consent of Seller so long as such
communication or contact is not reasonably expected to cause an inspection of
the Property by such Authorities, provided that, if Purchaser becomes aware that
an inspection by any of such Authorities is likely as a result of Purchaser's
request for information, then Purchaser shall withdraw such request and not
renew such request without first

<Page>

obtaining Seller's prior written consent. Notwithstanding anything to the
contrary contained herein, no physical testing or sampling shall be conducted
during any such entry by Purchaser or any Licensee Party upon the Real Property
without Seller's specific prior written consent, which consent shall not be
unreasonably withheld or delayed.

     SECTION 5.2    DOCUMENT REVIEW.

            (a)     During the Evaluation Period, Purchaser and the Licensee
Parties shall have the right to review and inspect lease files, including,
without limitation, Tenant correspondence files, construction or space plans,
surveys, diagrams and schematics for the Property, and a list of all major
repairs (in excess of $5,000) of a capital nature during the three (3) years
prior to the Effective Date for the Property, at Purchaser's sole cost and
expense, all of which, to Seller's Knowledge, are in Seller's possession or
control. Any inspections shall occur at one location in Houston, Texas to be
designated by Seller. The following documents, all of which, to Seller's
Knowledge, are in Seller's possession or control, shall be delivered to
Purchaser and the Licensee Parties for review: the Environmental Reports (which
Purchaser shall have the right to have updated at Purchaser's sole cost and
expense); engineering reports and studies commissioned by Seller; real estate
tax bills, together with assessments (special or otherwise), ad valorem and
personal property tax bills, covering the period of Seller's ownership of the
Property; Operating Statements; and the Leases, Leasing Commission Agreements,
Service Contracts, Spectrasite Agreements, Construction Contracts, Licenses and
Permits. The foregoing materials that are either made available or delivered to
Purchaser are collectively referred to as the "DOCUMENTS." Subject to Section
7.4, Purchaser shall not have the right to review or inspect materials not
directly related to the leasing, maintenance and/or management of the Property,
including, without limitation, any of Seller's internal memoranda, financial
projections, budgets, appraisals, proposals for work not actually undertaken,
accounting and tax records and similar proprietary, elective or confidential
information.

            (b)     Purchaser acknowledges that any and all of the Documents may
be proprietary and confidential in nature and have been provided to Purchaser
solely to assist Purchaser in determining the desirability of purchasing the
Property. Subject only to the provisions of Article XII, Purchaser agrees not to
disclose the contents of the Documents or any of the provisions, terms or
conditions contained therein to any party outside of Purchaser's organization
other than its attorneys, partners, accountants, engineers, consultants, lenders
or investors (collectively, for purposes of this Section 5.2(b), the "PERMITTED
OUTSIDE PARTIES"). Purchaser further agrees that within its organization, or as
to the Permitted Outside Parties, the Documents will be disclosed and exhibited
only to those persons within Purchaser's organization or to those Permitted
Outside Parties who are responsible for determining the desirability of
Purchaser's acquisition of the Property. Purchaser further acknowledges that the
Documents and other information relating to the leasing arrangements between
Seller and Tenants are proprietary and confidential in nature. Purchaser agrees
not to divulge the contents of such Documents and other information except in
strict accordance with the confidentiality standards set forth in this Section
5.2 and Article XII. In permitting Purchaser and the Permitted Outside Parties
to review the Documents and other information to assist Purchaser, Seller has
not waived any privilege or

<Page>

claim of confidentiality with respect thereto, and no third party benefits or
relationships of any kind, either express or implied, have been offered,
intended or created by Seller, and any such claims are expressly rejected by
Seller and waived by Purchaser and the Permitted Outside Parties, for whom, by
its execution of this Agreement, Purchaser is acting as an agent with regard to
such waiver.

            (c)     Purchaser acknowledges that some of the Documents may have
been prepared by third parties and may have been prepared prior to Seller's
ownership of the Property. PURCHASER HEREBY ACKNOWLEDGES THAT, EXCEPT AS MAY BE
EXPRESSLY SET FORTH IN SECTION 8.1 BELOW, SELLER HAS NOT MADE AND DOES NOT MAKE
ANY REPRESENTATION OR WARRANTY REGARDING THE TRUTH, ACCURACY OR COMPLETENESS OF
THE DOCUMENTS OR THE SOURCES THEREOF. EXCEPT AS MAY BE EXPRESSLY SET FORTH IN
SECTION 8.1 BELOW, SELLER HAS NOT UNDERTAKEN ANY INDEPENDENT INVESTIGATION AS TO
THE TRUTH, ACCURACY OR COMPLETENESS OF THE DOCUMENTS AND IS PROVIDING THE
DOCUMENTS SOLELY AS AN ACCOMMODATION TO PURCHASER.

     SECTION 5.3    ENTRY AND INSPECTION OBLIGATIONS; TERMINATION OF AGREEMENT.

            (a)     Purchaser agrees that in entering upon and inspecting or
examining the Property, Purchaser and the other Licensee Parties will not
materially disturb the Tenants or materially interfere with the use of the
Property pursuant to the Leases; materially interfere with the operation and
maintenance of the Real Property or Improvements; damage any part of the
Property or any personal property owned or held by Tenants or any other person
or entity; injure or otherwise cause bodily harm to Seller or any Tenant, or to
any of their respective agents, guests, invitees, contractors and employees, or
to any other person or entity; permit any liens to attach to the Real Property
by reason of the exercise of Purchaser's rights under this Article V; or reveal
or disclose any information obtained concerning the Property and the Documents
to anyone outside Purchaser's organization, except in accordance with the
confidentiality standards set forth in Section 5.2(b) and Article XII. Purchaser
will, and shall cause its contractors to, maintain comprehensive general
liability (occurrence) insurance in the amount of not less than Three Million
Dollars ($3,000,000) in respect to bodily injury (including death) and not less
than Three Million Dollars ($3,000,000) for property damage and on terms
reasonably satisfactory to Seller, and Workers' Compensation insurance in
statutory limits, and, if Purchaser or any Licensee Party performs any physical
inspection or sampling at the Real Property, in accordance with Section 5.1,
Purchaser shall maintain (if applicable), and shall cause the relevant Licensee
Parties to maintain, errors and omissions insurance and contractor's pollution
liability insurance in an amount of not less than Two Million Dollars
($2,000,000) and on terms acceptable to Seller. In each case (other than with
respect to Worker's Compensation insurance), such policies shall insure Seller,
Purchaser, Mack-Cali Sub XVII, Inc., M-C Texas Management L.P. and such other
parties as Seller shall reasonably request, and Purchaser shall deliver to
Seller evidence of insurance verifying such coverage prior to entry upon the
Real Property or Improvements. Purchaser shall also (i) promptly pay when due
the costs of all entry and inspections and

<Page>

examinations done with regard to the Property; (ii) cause any inspection to be
conducted in accordance with standards customarily employed in the industry and
in compliance with all Governmental Regulations; (iii) at Seller's request,
furnish to Seller any studies, reports or test results received by Purchaser
regarding the Property, promptly after such receipt, in connection with such
inspection; and (iv) restore the Real Property and Improvements to the condition
in which the same were found before any such entry upon the Real Property and
inspection or examination was undertaken.

            (b)     Purchaser hereby indemnifies, defends and holds Seller and
its partners, agents, directors, officers, employees, successors and assigns
harmless from and against any and all liens, claims, causes of action, damages,
liabilities, demands, suits, and obligations to third parties, together with all
losses, penalties, costs and expenses relating to any of the foregoing
(including but not limited to court costs and reasonable attorneys' fees),
arising out of any inspections, investigations, examinations, sampling or tests
conducted by Purchaser or any of the Licensee Parties, whether prior to or after
the date hereof, with respect to the Property or any violation of the provisions
of this Article V.

            (c)     In the event that Purchaser determines, after its inspection
of the Documents and Real Property and Improvements, that it does not want to
proceed with the transaction as set forth in this Agreement, Purchaser shall
have the right to terminate this Agreement by providing written notice to Seller
prior to the expiration of the Evaluation Period. In the event Purchaser
terminates this Agreement with respect to the Property in accordance with this
Section 5.3(c), or under any other right of termination as set forth herein,
Purchaser shall have the right to receive a refund of the Earnest Money Deposit,
together with all interest which has accrued thereon, and except with respect to
the Termination Surviving Obligations, this Agreement shall be null and void and
the parties shall have no further obligation to each other. In the event this
Agreement is terminated, Purchaser shall return to Seller all copies Purchaser
has made of the Documents and, provided that Seller pays for such reports,
studies and test results, all copies of any studies, reports or test results
regarding any part of the Property obtained by Purchaser, before or after the
execution of this Agreement, in connection with Purchaser's inspection of the
Property (collectively, "PURCHASER'S INFORMATION") promptly following the time
this Agreement is terminated for any reason, provided that Seller acknowledges
that any materials delivered to Seller by Purchaser pursuant to the provisions
of this Section 5.3(c) shall be without warranty or representation whatsoever.

     SECTION 5.4    SALE "AS IS." THE TRANSACTION CONTEMPLATED BY THIS AGREEMENT
HAS BEEN NEGOTIATED BETWEEN SELLER AND PURCHASER. THIS AGREEMENT REFLECTS THE
MUTUAL AGREEMENT OF SELLER AND PURCHASER, AND PURCHASER HAS THE RIGHT TO CONDUCT
ITS OWN INDEPENDENT EXAMINATION OF THE PROPERTY. OTHER THAN THE MATTERS
EXPRESSLY REPRESENTED IN SECTION 8.1 HEREOF, BY WHICH ALL OF THE FOLLOWING
PROVISIONS OF THIS SECTION 5.4 ARE LIMITED, PURCHASER HAS NOT RELIED UPON AND
WILL NOT RELY UPON, EITHER DIRECTLY OR INDIRECTLY, ANY REPRESENTATION OR
WARRANTY OF

<Page>

SELLER OR ANY OF SELLER'S AGENTS OR REPRESENTATIVES, AND PURCHASER HEREBY
ACKNOWLEDGES THAT NO SUCH REPRESENTATIONS OR WARRANTIES HAVE BEEN MADE.

     EXCEPT AS MAY BE EXPRESSLY SET FORTH IN SECTION 8.1 BELOW OR IN THE
DOCUMENTS TO BE DELIVERED AT CLOSING PURSUANT TO SECTIONS 10.3(a), (b), (c),
(d), (f), (g), (i), AND (j), SELLER SPECIFICALLY DISCLAIMS, AND NEITHER SELLER
NOR ANY OF SELLER'S AFFILIATES NOR ANY OTHER PERSON IS MAKING, ANY
REPRESENTATION, WARRANTY OR ASSURANCE WHATSOEVER TO PURCHASER, AND NO WARRANTIES
OR REPRESENTATIONS OF ANY KIND OR CHARACTER, EITHER EXPRESS OR IMPLIED, ARE MADE
BY SELLER OR RELIED UPON BY PURCHASER WITH RESPECT TO THE STATUS OF TITLE TO OR
THE MAINTENANCE, REPAIR, CONDITION, DESIGN OR MARKETABILITY OF THE PROPERTY, OR
ANY PORTION THEREOF, INCLUDING BUT NOT LIMITED TO (a) ANY IMPLIED OR EXPRESS
WARRANTY OF MERCHANTABILITY, (b) ANY IMPLIED OR EXPRESS WARRANTY OF FITNESS FOR
A PARTICULAR PURPOSE, (c) ANY IMPLIED OR EXPRESS WARRANTY OF CONFORMITY TO
MODELS OR SAMPLES OF MATERIALS, (d) ANY RIGHTS OF PURCHASER UNDER APPROPRIATE
STATUTES TO CLAIM DIMINUTION OF CONSIDERATION, (e) ANY CLAIM BY PURCHASER FOR
DAMAGES BECAUSE OF DEFECTS, WHETHER KNOWN OR UNKNOWN, WITH RESPECT TO THE
IMPROVEMENTS OR THE PERSONAL PROPERTY, (f) THE FINANCIAL CONDITION OR PROSPECTS
OF THE PROPERTY AND (g) THE COMPLIANCE OR LACK THEREOF OF THE REAL PROPERTY OR
THE IMPROVEMENTS WITH GOVERNMENTAL REGULATIONS, INCLUDING WITHOUT LIMITATION
ENVIRONMENTAL LAWS, NOW EXISTING OR HEREAFTER ENACTED OR PROMULGATED, IT BEING
THE EXPRESS INTENTION OF SELLER AND PURCHASER THAT, EXCEPT AS EXPRESSLY SET
FORTH IN THIS AGREEMENT, THE PROPERTY WILL BE CONVEYED AND TRANSFERRED TO
PURCHASER IN ITS PRESENT CONDITION AND STATE OF REPAIR, "AS IS" AND "WHERE IS,"
WITH ALL FAULTS. PURCHASER REPRESENTS THAT IT IS A KNOWLEDGEABLE, EXPERIENCED
AND SOPHISTICATED PURCHASER OF REAL ESTATE, AND THAT IT IS RELYING SOLELY ON ITS
OWN EXPERTISE AND THAT OF PURCHASER'S CONSULTANTS IN PURCHASING THE PROPERTY.
PURCHASER HAS BEEN GIVEN A SUFFICIENT OPPORTUNITY HEREIN TO CONDUCT AND HAS
CONDUCTED OR WILL CONDUCT SUCH INSPECTIONS, INVESTIGATIONS AND OTHER INDEPENDENT
EXAMINATIONS OF THE PROPERTY AND RELATED MATTERS AS PURCHASER DEEMS NECESSARY,
INCLUDING BUT NOT LIMITED TO THE PHYSICAL AND ENVIRONMENTAL CONDITIONS THEREOF,
AND WILL RELY UPON SAME AND NOT UPON ANY STATEMENTS OF SELLER (EXCLUDING THE
MATTERS EXPRESSLY REPRESENTED BY SELLER IN SECTION 8.1 HEREOF) NOR OF ANY
OFFICER, DIRECTOR, EMPLOYEE, AGENT OR ATTORNEY OF SELLER. PURCHASER ACKNOWLEDGES
THAT ALL INFORMATION OBTAINED

<Page>

BY PURCHASER WAS OBTAINED FROM A VARIETY OF SOURCES, AND, EXCEPT AS MAY BE
EXPRESSLY SET FORTH IN SECTION 8.1 BELOW, SELLER WILL NOT BE DEEMED TO HAVE
REPRESENTED OR WARRANTED THE COMPLETENESS, TRUTH OR ACCURACY OF ANY OF THE
DOCUMENTS OR OTHER SUCH INFORMATION HERETOFORE OR HEREAFTER FURNISHED TO
PURCHASER. UPON CLOSING, PURCHASER WILL ASSUME THE RISK THAT ADVERSE MATTERS,
INCLUDING, BUT NOT LIMITED TO, ADVERSE PHYSICAL AND ENVIRONMENTAL CONDITIONS,
MAY NOT HAVE BEEN REVEALED BY PURCHASER'S INSPECTIONS AND INVESTIGATIONS.
PURCHASER ACKNOWLEDGES AND AGREES THAT, UPON CLOSING, SELLER WILL SELL AND
CONVEY TO PURCHASER, AND PURCHASER WILL ACCEPT THE PROPERTY, "AS IS, WHERE IS,"
WITH ALL FAULTS. PURCHASER FURTHER ACKNOWLEDGES AND AGREES THAT THERE ARE NO
ORAL AGREEMENTS, WARRANTIES OR REPRESENTATIONS COLLATERAL TO OR AFFECTING THE
PROPERTY BY SELLER, ANY AGENT OF SELLER OR ANY THIRD PARTY. SELLER IS NOT LIABLE
OR BOUND IN ANY MANNER BY ANY ORAL OR WRITTEN STATEMENTS, REPRESENTATIONS OR
INFORMATION PERTAINING TO THE PROPERTY FURNISHED BY ANY REAL ESTATE BROKER,
AGENT, EMPLOYEE OR OTHER PERSON, UNLESS THE SAME ARE SPECIFICALLY SET FORTH OR
REFERRED TO HEREIN. PURCHASER ACKNOWLEDGES THAT THE PURCHASE PRICE REFLECTS THE
"AS IS, WHERE IS" NATURE OF THIS SALE AND ANY FAULTS, LIABILITIES, DEFECTS OR
OTHER ADVERSE MATTERS THAT MAY BE ASSOCIATED WITH THE PROPERTY. PURCHASER, WITH
PURCHASER'S COUNSEL, HAS FULLY REVIEWED THE DISCLAIMERS AND WAIVERS SET FORTH IN
THIS AGREEMENT AND UNDERSTANDS THEIR SIGNIFICANCE AND AGREES THAT THE
DISCLAIMERS AND OTHER AGREEMENTS SET FORTH HEREIN ARE AN INTEGRAL PART OF THIS
AGREEMENT, AND THAT SELLER WOULD NOT HAVE AGREED TO SELL THE PROPERTY TO
PURCHASER FOR THE PURCHASE PRICE WITHOUT THE DISCLAIMERS AND OTHER AGREEMENTS
SET FORTH IN THIS AGREEMENT.

     PURCHASER AND PURCHASER'S AFFILIATES FURTHER COVENANT AND AGREE NOT TO SUE
SELLER AND SELLER'S AFFILIATES AND RELEASE SELLER AND SELLER'S AFFILIATES OF AND
FROM AND WAIVE ANY CLAIM OR CAUSE OF ACTION, INCLUDING WITHOUT LIMITATION ANY
STRICT LIABILITY CLAIM OR CAUSE OF ACTION, THAT PURCHASER OR PURCHASER'S
AFFILIATES MAY HAVE AGAINST SELLER OR SELLER'S AFFILIATES UNDER ANY
ENVIRONMENTAL LAW, NOW EXISTING OR HEREAFTER ENACTED OR PROMULGATED, RELATING TO
ENVIRONMENTAL MATTERS OR ENVIRONMENTAL CONDITIONS IN, ON, UNDER, ABOUT OR
MIGRATING FROM OR ONTO THE PROPERTY, INCLUDING, WITHOUT LIMITATION, THE
COMPREHENSIVE ENVIRONMENTAL RESPONSE, COMPENSATION AND LIABILITY ACT, OR BY
VIRTUE OF ANY COMMON LAW RIGHT, NOW EXISTING OR HEREAFTER CREATED, RELATED TO

<Page>

ENVIRONMENTAL CONDITIONS OR ENVIRONMENTAL MATTERS IN, ON, UNDER, ABOUT OR
MIGRATING FROM OR ONTO THE PROPERTY. NOTWITHSTANDING THE PRECEDING SENTENCE, IF
PURCHASER OR ANY OF PURCHASER'S AFFILIATES IS THE SUBJECT OF ANY CLAIM OR CAUSE
OF ACTION BY A THIRD PARTY UNAFFILIATED WITH PURCHASER (INCLUDING, WITHOUT
LIMITATION, ANY GOVERNMENTAL ENTITY) THAT ALLEGES A WRONGFUL ACT BY SELLER
DURING SELLER'S PERIOD OF OWNERSHIP OF THE PROPERTY, THEN PURCHASER OR
PURCHASER'S AFFILIATES, AS APPLICABLE, MAY SEEK CONTRIBUTORY DAMAGES FROM SELLER
WITH RESPECT TO SUCH CLAIM OR CAUSE OF ACTION. THE TERMS AND CONDITIONS OF THIS
SECTION 5.4 WILL EXPRESSLY SURVIVE THE TERMINATION OF THIS AGREEMENT OR THE
CLOSING, AS THE CASE MAY BE, AND WILL NOT MERGE WITH THE PROVISIONS OF ANY
CLOSING DOCUMENTS AND ARE HEREBY DEEMED INCORPORATED INTO THE DEED AS FULLY AS
IF SET FORTH AT LENGTH THEREIN.

                                   ARTICLE VI
                            TITLE AND SURVEY MATTERS

     SECTION 6.1    SURVEY. Purchaser acknowledges receipt of the Existing
Survey. Any modification, update or recertification of the Existing Survey shall
be at Purchaser's election and sole cost and expense. The Existing Survey
together with each update Purchaser has elected to obtain, if any, is herein
referred to as the "UPDATED SURVEY."

     SECTION 6.2    TITLE COMMITMENT.

            (a)     Purchaser acknowledges receipt of that certain title
insurance commitment dated April 9, 2002 issued by the Title Company under
Commitment No. 673945-F (the "TITLE COMMITMENT"), together with copies of the
title exceptions listed thereon. Purchaser shall have until the expiration of
the Evaluation Period (the "ORIGINAL OBJECTION DATE") to send written notice to
Seller of its objections to matters shown on the Title Commitment or the
Existing Survey that Purchaser deems unacceptable and shall have until the date
(the "NEW OBJECTION DATE") that is five (5) Business Days after receipt by
Purchaser's counsel of any update to the Title Commitment or any Updated Survey
(or as promptly as possible prior to the Closing with respect to updates
received less than five (5) Business Days prior to the Closing) to send written
notice to Seller of Purchaser's objections to any new exceptions to title to the
Real Property raised thereby, provided that Purchaser may object to matters
shown on an Updated Survey only if such matters were not shown on the Existing
Survey. Purchaser's objections made in accordance with the preceding sentence
are referred to herein as "TITLE OBJECTIONS" or "SURVEY OBJECTIONS," as
applicable. Purchaser will be deemed to have accepted the exceptions to title
set forth on the Title Commitment (as updated) and the matters shown on the
Existing Survey and Updated Survey as permitted exceptions (together with any
Title Objections and Survey Objections ultimately waived by Purchaser or cured
by Seller, the "PERMITTED EXCEPTIONS") unless such matters are objected to by
Purchaser in writing by the Original Objection Date or the

<Page>

New Objection Date, as applicable. Seller shall cause the Title Company to
furnish to Purchaser a preliminary title report or title commitment, by the
terms of which the Title Company agrees to issue to Purchaser at Closing an
owner's policy of title insurance (the "TITLE POLICY") in the amount of the
Purchase Price on the then standard TLTA owner's form insuring Purchaser's fee
simple title to the Real Property, subject to the terms of such policy and the
Permitted Exceptions including, without limitation, the standard or general
exceptions. The basic premium for the Title Policy shall be at Seller's expense,
and Purchaser may request additional coverage under the Title Policy or
endorsements or deletions thereto (including, without limitation, the
modification or deletion of the survey exception), which shall be, in each case,
at Purchaser's expense.

            (b)     All taxes, water rates or charges, sewer rents and
assessments, plus interest and penalties thereon, which on the Closing Date are
liens against the Real Property and which Seller is obligated to pay and
discharge will be credited against the Purchase Price (subject to the provision
for apportionment of taxes, water rates and sewer rents herein contained) and
shall not be deemed a Title Objection. If on the Closing Date there shall be
financing statements evidencing security interests filed against the Property,
such items shall not be Title Objections if (i) the personal property or
fixtures covered by such security interests are no longer in or on the Real
Property, or (ii) such personal property or fixtures are the property of a
Tenant, and Purchaser fails to object to such security interest prior to the
expiration of the Evaluation Period, or (iii) the financing statement was filed
more than five (5) years prior to the Closing Date and was not renewed.

            (c)     If on the Closing Date the Real Property shall be affected
by any lien which, pursuant to the provisions of this Agreement, is required to
be discharged or satisfied by Seller, Seller shall not be required to discharge
or satisfy the same of record provided the money necessary to satisfy the lien
is retained by the Title Company at Closing, and the Title Company either omits
the lien as an exception from the Title Commitment or insures against collection
thereof from out of the Real Property and Improvements, and a credit is given to
Purchaser for the recording charges for a satisfaction or discharge of such
lien.

            (d)     No franchise, transfer, inheritance, income, corporate or
other tax (other than ad valorem taxes) open, levied or imposed against Seller
or any former owner of the Property, that may be a lien against the Property on
the Closing Date, shall be an objection to title if the Title Company insures
against collection thereof from or out of the Real Property and/or the
Improvements, and provided further that Seller deposits with the Title Company a
sum reasonably sufficient to secure a release of the Property from the lien
thereof. If a search of title discloses judgments, bankruptcies, or other
returns against other persons having names the same as or similar to that of
Seller, Seller will deliver to Purchaser an affidavit stating that such
judgments, bankruptcies or other returns do not apply to Seller, and such search
results shall not be deemed Title Objections.

<Page>

     SECTION 6.3    TITLE DEFECT.

            (a)     In the event Seller receives any Survey Objection or Title
Objection (collectively and individually, a "TITLE DEFECT") within the time
periods required under Section 6.2 above, Seller may elect (but shall not be
obligated) to attempt to remove, or cause to be removed at its expense, any such
Title Defect, and shall provide Purchaser with notice, within seven (7) days of
its receipt of any such objection, of its intention to cure any such Title
Defect. If Seller elects to attempt to cure any Title Defect, the Scheduled
Closing Date shall be extended for a period not to exceed thirty (30) days. In
the event that (i) Seller elects not to attempt to cure any such Title Defect,
or (ii) Seller is unable to cure any such Title Defect for any period elected by
Seller but not to exceed thirty (30) days from the Scheduled Closing Date,
Seller shall so advise Purchaser and Purchaser shall have the right to terminate
this Agreement and receive a refund of the Earnest Money Deposit, together with
all interest which has accrued thereon, or to waive such Title Defect and
proceed to the Closing. Purchaser shall make such election within seven (7) days
after receipt of Seller's notice. If Purchaser elects to proceed to the Closing,
any Title Defects waived by Purchaser shall be deemed Permitted Exceptions. In
any such event of termination, Purchaser shall promptly return Purchaser's
Information to Seller, after which neither party shall have any further
obligation to the other under this Agreement except for the Termination
Surviving Obligations.

            (b)     Notwithstanding any provision of this Article VI to the
contrary, Seller will be obligated to cure exceptions to title to the Property,
in the manner described above, relating to liens and security interests securing
any financings to Seller, and any mechanic's liens resulting from work at the
Property commissioned by Seller, its managing agents or its affiliates.

                                   ARTICLE VII
             INTERIM OPERATING COVENANTS, ESTOPPELS AND POST-CLOSING
                                   MANAGEMENT

     SECTION 7.1    INTERIM OPERATING COVENANTS. Seller covenants to Purchaser
that Seller will:

            (a)     OPERATIONS. From the Effective Date until Closing, continue
to operate, manage and maintain the Improvements in the ordinary course of
Seller's business and substantially in accordance with Seller's present
practice, subject to ordinary wear and tear and further subject to Article XI of
this Agreement.

            (b)     COMPLIANCE WITH GOVERNMENTAL REGULATIONS. From the Effective
Date until Closing, not knowingly take any action that would result in a failure
to comply in all material respects with all Governmental Regulations applicable
to the Property, it being understood and agreed that prior to Closing, Seller
will have the right to contest any such Governmental Regulations.

            (c)     SECURITY DEPOSITS AND REAL ESTATE TAX APPEALS. From the
Effective Date to the date that is two (2) Business Days prior to the expiration
of the Evaluation Period,

<Page>

Seller will notify Purchaser of any real estate tax appeals settled during such
period or the application of a Security Deposit in the event of a default by a
Tenant. From and after the date that is two (2) Business Days prior to the
expiration of the Evaluation Period, Seller shall not settle any tax appeal or
apply a Security Deposit in the event of a default by a Tenant without
Purchaser's prior written consent, which shall not be unreasonably withheld,
conditioned or delayed and which shall be deemed to have been given if Purchaser
has not responded to Seller's notice within five (5) Business Days after receipt
thereof. Notwithstanding anything to the contrary contained in this Agreement,
Purchaser's consent will not be required in connection with (i) the settlement
of a tax appeal in the event that the settlement results in an assessed value
that is equal to or less than the assessed value of the Real Property and
Improvements that was used by the taxing authority to calculate taxes owed for
the calendar year prior to the year in which the Closing occurs, or (ii) the
initiation of any real estate tax appeal contesting the assessments of the
Property as set forth in EXHIBIT Q attached hereto.

            (d)     CONSTRUCTION CONTRACTS. After the Effective Date, Seller may
not enter into any new Construction Contract without Purchaser's prior written
consent. New Construction Contracts containing material modifications to the
form contract and amendments to existing Construction Contracts shall be subject
to Purchaser's prior written consent, which may not be unreasonably withheld,
conditioned or delayed and which shall be deemed to have been given if Purchaser
has not responded to Seller's notice within five (5) Business Days after receipt
thereof. Seller shall promptly provide Purchaser with copies of any such new
Construction Contracts and amendments, provided that Purchaser shall have no
liability for any payment obligations thereunder unless Purchaser is given a
credit at Closing for all payments that may come due post-Closing, in which
event Purchaser shall assume such payment obligations to the extent of the
credit received by Purchaser.

            (e)     LEASING COMMISSION AGREEMENTS. After the Effective Date,
Seller may amend any Leasing Commission Agreement and enter into any new Leasing
Commission Agreement, without Purchaser's prior written consent, provided that
Purchaser shall have no liability for any commissions thereunder.

            (f)     LEASES. From the Effective Date to the Closing Date, Seller
will provide Purchaser with copies of any new Leases and amendments to existing
Leases. Seller shall have the right to enter into new Leases and Lease
amendments that are outlined on EXHIBIT T attached hereto. Purchaser's prior
written consent shall be required for Seller to enter into new Leases or Lease
amendments that are not outlined on EXHIBIT T, which Purchaser may withhold in
its sole discretion. Purchaser's consent shall be deemed to have been given if
Purchaser has not responded to Seller's request for consent within five (5)
Business Days after receipt of the proposed new Lease or Lease amendment.

            (g)     SERVICE CONTRACTS. From the Effective Date to the Closing
Date, Seller may enter into any new Service Contract that terminates or is
terminable at or before the Closing Date. If an emergency exists at the Property
and, despite Seller's best efforts working with the vendor, the vendor will not
agree to terminate the Service Contract at or before the Closing Date,

<Page>

then Purchaser's consent to such new Service Contract may not be unreasonably
withheld and will be deemed to have been given if Purchaser has not responded to
Seller's request within two (2) Business Days, provided that Purchaser shall
have no obligation to assume any such Service Contract.

            (h)     NOTICES. To the extent received by Seller, from the
Effective Date until Closing, promptly deliver to Purchaser copies of written
default notices, notices of lawsuits, notices of violations affecting the
Property and any other written notice of repairs or improvements required by an
insurance company.

     SECTION 7.2    ESTOPPELS.

            (a)     Seller shall send estoppel certificates (each, an "ESTOPPEL
CERTIFICATE") in the form attached hereto as EXHIBIT G (the "FORM TENANT
ESTOPPEL CERTIFICATE") to each Tenant occupying space at the Property on the
Effective Date. It shall be a condition precedent to Purchaser's obligation to
purchase the Property pursuant to this Agreement that Seller provide to
Purchaser, prior to Closing, Estoppel Certificates executed by the Major Tenants
and all other Tenants (all Tenants which are not Major Tenants are herein
referred to as the "OTHER TENANTS"). An Estoppel Certificate executed by any
Tenant shall satisfy the condition set forth immediately above in this Section
7.2(a) if it is in substantially the form of the Form Tenant Estoppel
Certificate as the same may be modified as necessary to reflect any factual
inconsistencies with the statements set forth therein which are necessary to
make such certificates accurate and complete as of such date, provided such
modifications are not inconsistent with the relevant Lease and any other
representations made herein by Seller with respect to such Lease, provided,
however, that an Estoppel Certificate executed by any Tenant shall be deemed to
satisfy the condition of this Section 7.2(a) so long as it is in the form or
contains such specified information as the applicable Lease requires such Tenant
to provide and/or contains the qualification by such Tenant of any statement as
being to its knowledge or as being subject to any similar qualification. If any
modification made to the Form Tenant Estoppel Certificate discloses a material
default by Seller under a Lease or materially and adversely affects the net
income of the Property, then Purchaser may terminate this Agreement by written
notice to Seller and receive the prompt return of the Earnest Money Deposit from
the Escrow Agent, together with the interest earned thereon, whereupon Purchaser
and Seller will have no further rights or obligations under this Agreement,
except with respect to the Termination Surviving Obligations; provided, however,
that if such modification discloses a default by Seller under this Agreement,
then Purchaser shall be entitled to all of its remedies under Section 13.1; but
provided further that if such modification discloses a default under this
Agreement by Seller that can be cured by the expenditure or payment of money,
then Purchaser will not have the right to terminate this Agreement as a result
thereof so long as Purchaser receives a credit at Closing in the amount required
to cure such default. In addition, if Seller is unable to deliver Estoppel
Certificates to Purchaser for any Major Tenants at Closing, then Purchaser may
terminate this Agreement by written notice to Seller and receive the prompt
return of the Earnest Money Deposit from the Escrow Agent, together with the
interest earned thereon, whereupon Purchaser and Seller will

<Page>

have no further rights or obligations under this Agreement, except with respect
to the Termination Surviving Obligations.

            (b)     In the event that Seller is unable to provide Estoppel
Certificates to Purchaser at the Closing for Other Tenants, Seller shall execute
and deliver to Purchaser certificates (each, a "SELLER ESTOPPEL CERTIFICATE")
substantially in the form attached hereto as EXHIBIT M (the "FORM SELLER
ESTOPPEL CERTIFICATE"), as the same may be modified by Seller prior to Closing
as necessary to reflect any factual inconsistencies with the statements set
forth therein which are necessary to make such certificates accurate and
complete as of such date, provided such modifications are not inconsistent with
the relevant Lease and any other representations made herein by Seller, covering
the particular Other Tenants so that Purchaser shall receive, at Closing, an
Estoppel Certificate or a Seller Estoppel Certificate with respect to all of the
Other Tenants. If Seller delivers Seller Estoppel Certificates to Purchaser in
connection with this Agreement, each statement therein shall survive for a
period terminating on the earlier of (i) twelve (12) months after the Closing
Date, or (ii) the date on which Purchaser has received an executed Estoppel
Certificate signed by the Tenant under the Lease in question which is consistent
with such statement contained in the Seller's Estoppel Certificate. If any
modification made by Seller to the Form Seller Estoppel Certificate discloses a
material default by Seller under a Lease or materially and adversely affects the
net income of the Property, then Purchaser may terminate this Agreement by
written notice to Seller and receive the prompt return of the Earnest Money
Deposit from the Escrow Agent, together with the interest earned thereon,
whereupon Purchaser and Seller will have no further rights or obligations under
this Agreement, except with respect to the Termination Surviving Obligations;
provided, however, that if such modification discloses a default by Seller under
this Agreement, then Purchaser shall be entitled to all of its remedies under
Section 13.1; but provided further that if such modification discloses a default
under this Agreement by Seller that can be cured by the expenditure or payment
of money, then Purchaser will not have the right to terminate this Agreement as
a result thereof so long as Purchaser receives a credit at Closing in the amount
required to cure such default. If Purchaser receives an Estoppel Certificate
which contains some but not all of the matters set forth in the Form Tenant
Estoppel Certificate (a "PARTIAL CERTIFICATE") and Seller provides a Seller
Estoppel Certificate for such Tenant, then (i) if the Partial Certificate is
received prior to Closing, the Seller Estoppel Certificate may omit matters
contained in the Partial Certificate, and (ii) if the Partial Certificate is
received after Closing, Seller's Estoppel Certificate shall cease to survive as
to the matters contained in the Partial Certificate which are consistent with
those matters contained in the Seller's Estoppel Certificate. If any Estoppel
Certificate contains statements confirming any of Seller's representations or
warranties herein, then Seller shall be relieved of any liability with respect
to any such representation or warranty.

            (c)     If any Estoppel Certificates or Seller Estoppel Certificates
contain statements or allegations that a default or potential default exists on
the part of Seller under the Lease in question or contain information
inconsistent with any representations of Seller contained in this Agreement and
Purchaser elects to close the transaction contemplated herein notwithstanding
the existence of such statements, allegations or information, then such Estoppel
Certificates and/or Seller Estoppel Certificates shall be deemed acceptable for
purposes of this

<Page>

Section 7.2, notwithstanding the existence of such allegations, statements or
information, and Seller shall have no liability to Purchaser hereunder with
respect to the existence of such allegations, statements or information. In
addition, (i) if any Estoppel Certificate or Seller Estoppel Certificate
contains information that was otherwise disclosed in the Documents delivered to
Purchaser during the Evaluation Period pursuant to Section 5.2, Purchaser shall
have no right to object to such Estoppel Certificate or Seller Estoppel
Certificate after the expiration of the Evaluation Period, and (ii) if any
Estoppel Certificate or Seller Estoppel Certificate reflects the fact that a
Tenant has not yet accepted or occupied the leased premises and/or has not yet
commenced paying rent because the tenant improvements with respect to the
relevant Lease have not yet been completed and/or that all requirements of the
landlord under the Lease are not complied with because the tenant improvements
are ongoing, but such Estoppel Certificate or Seller Estoppel Certificate does
not indicate that the landlord has committed a material default under the
relevant Lease, then Purchaser shall have no right to object to such Estoppel
Certificate or Seller Estoppel Certificate.

     SECTION 7.3    [INTENTIONALLY DELETED]

     SECTION 7.4    ADDITIONAL AUDITS. Purchaser shall have, in addition to any
inspection or audit rights contained elsewhere in this Agreement, the right to
conduct a full audit of the books and records of Seller relating to the
operations and financial results of the Property, in such form and at such time,
including up to 270 days after Closing, as Purchaser may reasonably determine is
necessary to comply with applicable securities laws requirements, including,
without limitation, 17 C.F.R. Section 210.3-14 promulgated under the Securities
Exchange Act of 1934, as amended. All costs incurred as a result of Purchaser
undertaking such audit shall be borne exclusively by Purchaser; provided,
however, that Seller shall make available such books, records and materials as
may be reasonably requested by Purchaser or its accountants in order to conduct
such audit. All such audit activities shall be conducted at Seller's or its
agent's place of business in a commercially reasonable fashion during normal
business hours and upon five (5) Business Days prior written notice from
Purchaser to Seller.

                                  ARTICLE VIII
                         REPRESENTATIONS AND WARRANTIES

     SECTION 8.1    SELLER'S REPRESENTATIONS AND WARRANTIES. Except for any
representations and warranties contained in the documents to be delivered at
Closing pursuant to Sections 10.3(a), (b), (c), (d), (f), (g), (i), and (j), the
following constitute the sole representations and warranties of Seller, which
representations and warranties shall be true as of the Effective Date and,
subject to Section 10.3(i), as of the Closing Date. Subject to the limitations
set forth in Section 8.3 of this Agreement, Seller represents and warrants to
Purchaser the following:

            (a)     STATUS. Seller is a limited partnership, duly organized and
validly existing under the laws of the State of Texas.

            (b)     AUTHORITY. The execution and delivery of this Agreement and
the performance of Seller's obligations hereunder have been duly authorized by
all necessary action

<Page>

on the part of Seller, and this Agreement constitutes the legal, valid and
binding obligation of Seller.

            (c)     NON-CONTRAVENTION. The execution and delivery of this
Agreement by Seller and the consummation by Seller of the transactions
contemplated hereby will not violate any judgment, order, injunction, decree,
regulation or ruling of any court or Authority or conflict with, result in a
breach of, or constitute a default under the organizational documents of Seller,
any note or other evidence of indebtedness, any mortgage, deed of trust or
indenture, or any lease or other material agreement or instrument to which
Seller is a party or by which it is bound.

            (d)     SUITS AND PROCEEDINGS; VIOLATIONS. Except as listed in
EXHIBIT H, there are no legal actions, suits or similar proceedings pending and
served, or to Seller's Knowledge, threatened in writing against Seller or the
Property which if adversely determined, would materially and adversely affect
the value of the Property or Seller's ability to consummate the transactions
contemplated hereby. To Seller's Knowledge, except as listed in EXHIBIT H,
Seller has not received any written notice from any Authorities of any
violations with respect to the Property of any Governmental Regulations that
have not been cured. There are no real estate tax appeals pending.

            (e)     NON-FOREIGN ENTITY. Seller is not a "foreign person" or
"foreign corporation" as those terms are defined in the Internal Revenue Code of
1986, as amended, and the regulations promulgated thereunder.

            (f)     TENANTS. As of the date of this Agreement, the only tenants
or users of all or any portion of the Property claiming rights pursuant to the
Leases are the tenants or users set forth in the Lease Schedule attached as
EXHIBIT F. EXHIBIT F contains a true and correct list of all Leases. The
Documents delivered to Purchaser pursuant to Section 5.2 hereof include true and
correct copies of all of the Leases. To Seller's Knowledge, any consents from
Seller to a Tenant with respect to any subleases are included in the Documents.
None of the Leases and none of the Rentals payable thereunder have been
assigned, pledged or encumbered by Seller.

            (g)     DEFAULTS. To Seller's Knowledge, all written default notices
to or from any Tenant are or will be included in the Documents. There are no
existing material defaults by Tenants under the Leases except as may be set
forth on the schedule of arrearages attached hereto as EXHIBIT K (the
"ARREARAGES SCHEDULE") other than the alleged default by Memorial Leasehold,
L.L.C. under its Lease at the Memorial Property caused by such Tenant's refusal
to pay additional rent pertaining to the excess cost of tenant improvements as
provided for in such Lease, and Seller has not received any written notice of
any landlord defaults under the Leases that have not been cured.

            (h)     SERVICE CONTRACTS AND SPECTRASITE AGREEMENTS. To Seller's
Knowledge, (i) none of the service providers listed on EXHIBIT E is in default
under any Service Contract and (ii) Seller is not in default under any Service
Contract. The Documents delivered to Purchaser pursuant to Section 5.2 hereof
include true and correct copies of all Spectrasite Agreements and

<Page>

all written Service Contracts under which Seller is currently paying for
services rendered in connection with the Property, and EXHIBIT E contains a true
and correct list of all Service Contracts. 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, which could be binding on
Purchaser after Closing, other than (x) the Spectrasite Agreements (if Purchaser
fails to comply with the requirements in Section 3.2) and (y) the Construction
Contracts (if Seller fulfills its obligations under the second sentence of
Section 3.2 and the second sentence of Section 10.3(i), as applicable).

            (i)     LEASING COMMISSION AGREEMENTS AND CONSTRUCTION CONTRACTS.
The Documents delivered to Purchaser pursuant to Section 5.2 hereof include true
and correct copies of all existing Leasing Commission Agreements and
Construction Contracts. EXHIBIT J contains a true and correct list of all
existing Leasing Commission Agreements, and EXHIBIT O contains a true and
correct list of all Construction Contracts.

            (j)     CONDEMNATION PROCEEDINGS. To Seller's Knowledge, Seller has
received no written notice of any condemnation or eminent domain proceeding
pending or threatened against the Property or any part thereof.

            (k)     LABOR AND EMPLOYMENT MATTERS. Neither Seller nor M-C Texas
Management L.P. is a party to any oral or written employment contracts or
agreements with respect to the Property, other than the Separation Agreements,
pursuant to which Purchaser shall have no obligations.

            (l)     BANKRUPTCY. Seller is not insolvent and has not (i) made a
general assignment for the benefit of creditors; (ii) filed a petition for
bankruptcy or commenced any other action seeking reorganization, arrangement,
adjustment, liquidation, dissolution or composition of it or its debts under any
debtor relief laws; or (iii) had any involuntary case, proceeding or other
action commenced against it that seeks to have any order for relief entered
against it, as debtor, under any debtor relief laws.

            (m)     LEASING COMMISSIONS. No brokerage or leasing commissions or
other compensations are due or payable to any person, firm, corporation or other
entity with respect to or on account of any of the Leases or any extensions or
renewals thereof other than pursuant to the Leasing Commission Agreements, which
will be fully satisfied by Seller at or before Closing, and there is no
continuing liability of Purchaser under the Leasing Commission Agreements after
Closing.

            (n)     ENVIRONMENTAL MATTERS. Except as set forth in the
Environmental Reports, to Seller's Knowledge, (i) Seller has received no written
notice of any currently existing violations of Environmental Laws with respect
to the Property or pending or threatened administrative or other legal
proceedings, including, without limitation, any enforcement proceeding under any
Environmental Laws concerning Hazardous Substances, relating to the Property, or
of any settlement thereof, and (ii) there are no underground storage tanks
located at the Property.

<Page>

            (o)     NO OPTIONS. To Seller's Knowledge, except as may be set
forth in the Leases, no third party has any option to purchase all or any
portion of the Property.

            (p)     OPERATING STATEMENTS. To Seller's Knowledge, the Operating
Statements delivered to Purchaser are true and accurate in all material
respects.

            (q)     NO NOTICES. To Seller's Knowledge, except as set forth on
EXHIBIT H, there are no unsatisfied written notices requiring any material
repairs, restorations or improvements at the Property from any insurance company
or governmental agency and Seller has not received any written notice from any
insurer of any defects or inadequacies in any part of the Property which
adversely affect its insurability.

            (r)     POST-CLOSING CONTRACTUAL OBLIGATIONS. Except as created by
this Agreement or as disclosed in the Documents delivered to Purchaser pursuant
to this Agreement, to Seller's Knowledge, there are no outstanding contractual
obligations binding on Seller that might, with notice, the passage of time, or
both, be binding on Purchaser and have a material adverse effect on the Property
from and after Closing.

     SECTION 8.2     PURCHASER'S REPRESENTATIONS AND WARRANTIES. Purchaser
represents and warrants to Seller the following:

            (a)     STATUS. Purchaser is a duly organized and validly existing
limited partnership under the laws of the State of Delaware and qualified to do
business in the State of Texas.

            (b)     AUTHORITY. The execution and delivery of this Agreement and
the performance of Purchaser's obligations hereunder have been duly authorized
by all necessary action on the part of Purchaser and this Agreement constitutes
the legal, valid and binding obligation of Purchaser.

            (c)     NON-CONTRAVENTION. The execution and delivery of this
Agreement by Purchaser and the consummation by Purchaser of the transactions
contemplated hereby will not violate any judgment, order, injunction, decree,
regulation or ruling of any court or Authority or conflict with, result in a
breach of or constitute a default under the organizational documents of
Purchaser, any note or other evidence of indebtedness, any mortgage, deed of
trust or indenture, or any lease or other material agreement or instrument to
which Purchaser is a party or by which it is bound.

            (d)     CONSENTS. No consent, waiver, approval or authorization is
required from any person or entity (that has not already been obtained) in
connection with the execution and delivery of this Agreement by Purchaser or the
performance by Purchaser of the transactions contemplated hereby.

     SECTION 8.3    SURVIVAL OF REPRESENTATIONS, WARRANTIES AND COVENANTS. The
representations and warranties of Seller set forth

<Page>

in Section 8.1, the covenants of Seller set forth in Sections 7.1 and 7.4, and
the certifications contained in any Seller estoppels delivered under the second
paragraph of Section 7.2 will survive the Closing for a period of twelve (12)
months, after which time they will merge into the Deed. Purchaser will not have
any right to bring any action against Seller as a result of any untruth or
inaccuracy of such representations, warranties or certifications, or any such
breach, unless and until the aggregate amount of all liability and losses
arising out of any such untruth or inaccuracy, or any such breach, exceeds
Twenty-Five Thousand Dollars ($25,000) for the Property; and then only to the
extent of such excess. In addition, in no event will Seller's liability for all
such breaches exceed, in the aggregate, the sum of One Million Dollars
($1,000,000) for the Property unless such liability is incurred due to
fraudulent acts of Seller, in which event such liability cap shall not apply.
Seller shall have no liability with respect to any such representation,
warranty, certification or covenant if, prior to the Closing, Purchaser has
actual knowledge of any breach of such representation, warranty, certification
or covenant, or any Document made available or delivered for Purchaser's review,
tenant estoppel certificate, due diligence test, investigation or inspection of
the Property by Purchaser or any Licensee Party, or written disclosure by Seller
or Seller's agents or employees discloses one or more facts that conflict with
any such representation, warranty, certification, or covenant, and Purchaser
nevertheless consummates the transaction contemplated by this Agreement. The
Closing Surviving Obligations and the Termination Surviving Obligations will
survive Closing or termination of this Agreement, as applicable, without
limitation unless a specified period is otherwise provided in this Agreement.
All other representations, warranties, covenants and agreements made or
undertaken by Seller under this Agreement, unless otherwise specifically
provided herein, will not survive the Closing but will be merged into the Deed
and other Closing documents delivered at the Closing.

                                   ARTICLE IX
                         CONDITIONS PRECEDENT TO CLOSING

     SECTION 9.1    CONDITIONS PRECEDENT TO OBLIGATION OF PURCHASER. The
obligation of Purchaser to consummate the transaction hereunder shall be subject
to the fulfillment on or before the Closing Date of all of the following
conditions, any or all of which may be waived by Purchaser in its sole
discretion:

            (a)     Seller shall have delivered to Escrow Agent all of the items
required to be delivered to Purchaser pursuant to the terms of this Agreement,
including but not limited to, those provided for in Section 10.3.

            (b)     All of the representations and warranties of Seller
contained in this Agreement shall be true and correct in all respects as of the
date of Closing (with appropriate modifications permitted under this Agreement
or modifications not materially adverse to Purchaser).

            (c)     Seller shall have performed and observed, in all material
respects, all covenants and agreements of this Agreement to be performed and
observed by Seller as of the Closing Date.

<Page>

            (d)     Purchaser shall have received a marked Title Commitment for
the Property from the Title Company identifying only Permitted Exceptions on the
Schedule B attached thereto.

            (e)     No legal action shall be pending or threatened in writing
seeking to challenge or restrain the transaction contemplated hereunder.

            (f)     After expiration of the Evaluation Period and prior to
Closing, no Major Tenant shall have become insolvent, made a general assignment
for the benefit of creditors, filed a petition for bankruptcy or commenced any
other action seeking reorganization, arrangement, adjustment, liquidation,
dissolution or composition of it or its debts under any debtor relief laws, or
had any involuntary case, proceeding or other action commenced against it that
seeks to have any order for relief entered against it, as debtor, under any
debtor relief laws.

     SECTION 9.2    CONDITIONS PRECEDENT TO OBLIGATION TO SELLER.

            (a)     The obligation of Seller to consummate the transaction
hereunder shall be subject to the fulfillment on or before the date of Closing
(or as otherwise provided) of all of the following conditions, any or all of
which may be waived by Seller in it sole discretion:

                    (i)    Escrow Agent shall have received the Purchase Price
            as adjusted pursuant to, and payable in the manner provided for, in
            this Agreement, and Purchaser shall have provided written authority
            to Escrow Agent to release such amount to Seller.

                    (ii)   Purchaser shall have delivered to Seller all of the
            items required to be delivered to Seller pursuant to the terms of
            this Agreement, including but not limited to, those provided for in
            Section 10.2.

                    (iii)  All of the representations and warranties of
            Purchaser contained in this Agreement shall be true and correct in
            all material respects as of the date of Closing (with appropriate
            modifications permitted under this Agreement or not materially
            adverse to Seller).

                    (iv)   Purchaser shall have performed and observed, in all
            material respects, all covenants and agreements of this Agreement to
            be performed and observed by Purchaser as of the Closing Date.

                    (v)    Purchaser shall have delivered to Seller, before the
            expiration of the Evaluation Period, a notice setting forth the
            names of those persons, if any, currently employed at the Property
            by Seller to whom Purchaser will make an offer of employment at a
            salary equal to or higher than such employee's current salary (the
            "EMPLOYEE NOTICE"), provided that Seller will provide Purchaser with
            a list of employees currently employed at the Property and their
            current salary during the Evaluation Period. If Purchaser intends to
            make no such offers, the

<Page>

            Purchaser shall so state in the Employee Notice. Purchaser shall
            have no obligation to offer employment to any employees of Seller or
            Seller's Affiliates.

            (b)     Notwithstanding Section 9.2(a) or any other provision in
this Agreement to the contrary, in the event that, on the Scheduled Closing
Date, all of the conditions precedent to Purchaser's obligation to close with
respect to the Property have not been satisfied, unless Purchaser proceeds to
Closing on the Scheduled Closing Date, thereby waiving any unsatisfied
conditions precedent, the Scheduled Closing Date will be automatically extended
to the fifteenth (15th) day thereafter (such 15-day period being referred to
herein as the "CONDITIONS PRECEDENT CURE PERIOD" and the last day of such 15-day
period being referred to herein as the "EXTENDED CLOSING DATE"). Upon the
expiration of the Conditions Precedent Cure Period, either (i) Purchaser shall
proceed to Closing on the Extended Closing Date if all conditions precedent have
been satisfied (or Purchaser may proceed to Closing even if all conditions
precedent have not yet been satisfied, thereby waiving all such unsatisfied
conditions precedent ) or (ii) if the conditions precedent have not yet been
satisfied (or waived by Purchaser), the Closing shall be further extended to the
fifteenth (15th) day after the Extended Closing Date (such 15-day period being
referred to herein as the "SECOND CONDITIONS PRECEDENT CURE PERIOD" and the last
day of such 15-day period being referred to herein as the "SECOND EXTENDED
CLOSING DATE"). Upon the expiration of the Second Conditions Precedent Cure
Period, either (x) Purchaser shall proceed to Closing on the Second Extended
Closing Date if all conditions precedent have been satisfied (or Purchaser may
proceed to Closing even if all conditions precedent have not yet been satisfied,
thereby waiving all such unsatisfied conditions precedent ) or (y) if the
conditions precedent have not yet been satisfied (or waived by Purchaser), this
Agreement shall terminate. This Agreement shall not, in any event, terminate for
failure of condition until the expiration of the Second Conditions Precedent
Cure Period.

            (c)     In the event of the termination of this Agreement under this
Section 9.2, Purchaser shall have a right to receive, within five (5) Business
Days thereafter, a refund of the Earnest Money Deposit, together with all
interest which has accrued thereon, and except with respect to the Termination
Surviving Obligations, this Agreement shall be null and void and the parties
shall have no further obligations to each other. Notwithstanding anything to the
contrary contained in this Agreement, in the event that a default by Seller
shall occur pursuant to Section 13.1, which default also constitutes the failure
of a condition precedent, the provisions of Section 13.1 shall govern and
control.

                                    ARTICLE X
                                     CLOSING

     SECTION 10.1   CLOSING. The consummation of the transaction contemplated by
this Agreement by delivery of documents and payments of money shall take place
at 1:00 p.m. Eastern Time on the Scheduled Closing Date at the offices of the
Escrow Agent. At Closing, the events set forth in this Article X will occur, it
being understood that the performance or tender of performance of all matters
set forth in this Article X are mutually concurrent conditions which may be
waived by the party for whose benefit they are intended. The acceptance of the
Deed by

<Page>

Purchaser shall be deemed to be full performance and discharge of each and every
agreement and obligation on the part of Seller to be performed hereunder unless
otherwise specifically provided herein.

     SECTION 10.2   PURCHASER'S CLOSING OBLIGATIONS. On the Closing Date,
Purchaser, at its sole cost and expense, will deliver the following items to
Seller at Closing as provided herein:

            (a)     The Purchase Price, after all adjustments are made as herein
provided, by Federal Reserve wire transfer of immediately available funds, in
accordance with the timing and other requirements of Section 3.3;

            (b)     A counterpart original of the Assignment of Leases, duly
executed by Purchaser;

            (c)     A counterpart original of the Assignment, duly executed by
Purchaser;

            (d)     Evidence reasonably satisfactory to Seller that the person
executing the Assignment of Leases, the Assignment, and the Tenant Notice
Letters on behalf of Purchaser has full right, power and authority to do so;

            (e)     Form of written notice executed by Purchaser and to be
addressed and delivered to the Tenants by Purchaser in accordance with Section
10.6 herein, (i) acknowledging the sale of the Property to Purchaser, (ii)
acknowledging that Purchaser has received and that Purchaser is responsible for
the Security Deposit (specifying the exact amount of the Security Deposit) and
(iii) indicating that rent should thereafter be paid to Purchaser and giving
instructions therefor (the "TENANT NOTICE LETTERS");

            (f)     A counterpart original of the Closing Statement, duly
executed by Purchaser;

            (g)     A certificate, dated as of the date of Closing, stating (i)
that the representations and warranties of Purchaser contained in Section 8.2
are true and correct in all material respects as of the Closing Date (with
appropriate modifications to reflect any changes therein) or identifying any
representation or warranty which is not, or no longer is, true and correct and
explaining the state of facts giving rise to the change and (ii) that Purchaser
has extended a written offer of employment to those persons listed on the
Employee Notice to be employed by Purchaser at a salary equal to or higher than
the salary such person was earning as Seller's employee as of the Closing Date.
In no event shall Purchaser be liable to Seller for, or be deemed to be in
default hereunder if any representation or warranty is not true and correct in
all material respects; PROVIDED, HOWEVER, that such event shall constitute the
non-fulfillment of the condition set forth in Section 9.2(a)(iii); PROVIDED
FURTHER that such limitation of liabilities and waiver of default in the event
of Closing shall not apply with respect to the representation and warranty set
forth in 10.2(g)(ii) above. If, despite changes or other matters described in
such certificate, the Closing occurs, Purchaser's representations and warranties
set forth in this Agreement shall be deemed to have been modified by all
statements made in such certificate; and

<Page>

            (h)     Such other documents as may be reasonably necessary or
appropriate to effect the consummation of the transaction which is the subject
of this Agreement.

     SECTION 10.3   SELLER'S CLOSING OBLIGATIONS. At the Closing, Seller will
deliver to Purchaser the following documents:

            (a)     A special warranty deed for the Property (the "DEED"), duly
executed and acknowledged by Seller, conveying to Purchaser the Real Property
and the Improvements subject only to the relevant Permitted Exceptions;

            (b)     A blanket assignment and bill of sale for the Property in
the form attached hereto as EXHIBIT C (each, a "BILL OF SALE"), duly executed by
Seller, assigning and conveying to Purchaser title to the Personal Property,
with special warranty of title;

            (c)     A counterpart original of an assignment and assumption of
Seller's interest, as lessor, in the Leases and Security Deposits for the
Property in the form attached hereto as EXHIBIT B (each, an "ASSIGNMENT OF
LEASES"), duly executed by Seller, conveying and assigning to Purchaser all of
Seller's right, title and interest, as lessor, in the Leases and Security
Deposits;

            (d)     A counterpart original of an assignment and assumption of
Seller's interest in the Spectrasite Agreements (if Purchaser fails to comply
with the requirements in Section 3.2), Construction Agreements (subject to a
credit at Closing in favor of Purchaser as set forth in Section 10.4(b)) and the
Licenses and Permits in the form attached hereto as EXHIBIT A (each, an
"ASSIGNMENT"), duly executed by Seller, conveying and assigning to Purchaser all
of Seller's right, title, and interest, if any, in the Construction Agreements
(if Seller fulfills its obligations under the second sentence of Section 3.2 and
the second sentence of Section 10.3(i), as applicable), the Licenses and Permits
and the Spectrasite Agreements (to the extent the Spectrasite Agreements pertain
to the Property and unless Purchaser complies with the requirements in Section
3.2);

            (e)     The Tenant Notice Letters, duly executed by Seller;

            (f)     Evidence reasonably satisfactory to Purchaser and Title
Company that the person executing the documents delivered by Seller pursuant to
this Section 10.3 on behalf of Seller has full right, power, and authority to do
so;

            (g)     A certificate in the form attached hereto as EXHIBIT I
("CERTIFICATE AS TO FOREIGN STATUS") certifying that Seller is not a "foreign
person" as defined in Section 1445 of the Internal Revenue Code of 1986, as
amended;

            (h)     All original Leases, Licenses and Permits, Leasing
Commission Agreements, Construction Agreements and Spectrasite Agreements
(unless Purchaser complies with the requirements in Section 3.2) in Seller's
possession (or copies where originals are not

<Page>

available), all of which may remain on site at the Property and need not be
delivered to the location of the Closing;

            (i)     A certificate, dated as of the date of Closing, stating that
the representations and warranties of Seller contained in Section 8.1 are true
and correct in all material respects as of the Closing Date (with appropriate
modifications as permitted by this Agreement to reflect any changes therein) or
identifying any representation or warranty which is not, or no longer is, true
and correct and explaining the state of facts giving rise to the change. In
addition, such certificate shall also include a representation by Seller, with
respect to any Construction Contracts for which a Construction Contract Estoppel
is not obtained by Seller in accordance with Section 3.2, that (1) the
Construction Contract is in full force and effect, (2) no material event of
default or any event that, with the giving of notice or passage of time could
become a material event of default, exists under such Construction Contract, and
(3) the balance due under such Construction Contract (which shall be stated in
such certification) is sufficient to complete the work contemplated by such
Construction Contract. Except in the event of fraud by Seller, Seller shall not
be liable to Purchaser for, or be deemed to be in default hereunder, if any
representation or warranty is not true and correct in all material respects;
provided, however, that such event shall constitute the non-fulfillment of the
condition set forth in Section 9.1(b), entitling Purchaser to terminate this
Agreement by written notice to Seller and receive the prompt return of the
Earnest Money Deposit from the Escrow Agent, together with the interest earned
thereon, whereupon Purchaser and Seller will have no further rights or
obligations under this Agreement, except with respect to the Termination
Surviving Obligations; and provided, further, that if such representation or
warranty is not true and correct in all material respects as a result of a
breach of this Agreement by Seller, rather than as a result of changing
circumstances not caused by Seller's breach, then Seller shall be in default
hereunder and Purchaser shall be entitled to all of its remedies under Section
13.1, unless such default can be cured by the expenditure or payment of money,
in which case Purchaser will not have the right to terminate this Agreement as a
result thereof so long as Purchaser receives a credit at Closing in the amount
required to cure such default. Notwithstanding anything herein to the contrary,
however, if, after the expiration of the Evaluation Period, any representation
and warranty provided by Seller in Sections 8.1(d) (except to the extent that
such legal actions, suits or proceedings are not adequately covered by insurance
and relate to (i) a violation of Environmental Laws, which, if adversely
determined, would materially and adversely affect the value of the Property or
(ii) Seller's ability to consummate the transaction contemplated hereby), or (h)
(first sentence only) above is no longer true and correct in all material
respects (with appropriate modifications as permitted by this Agreement to
reflect any changes therein) and is disclosed accordingly by Seller to
Purchaser, Purchaser shall not be entitled to terminate this Agreement. If,
despite changes or other matters described in such certificate, the Closing
occurs, Seller's representations and warranties set forth in this Agreement
shall be deemed to have been modified by all statements made in such
certificate; and

            (j)     The Lease Schedule, updated to show any changes, to Seller's
Knowledge, dated as of no more than one (1) Business Day prior to the Closing
Date.

<Page>

            (k)     Such affidavits or other documents as may reasonably be
required by the Title Company to issue the Title Policy subject only to the
Permitted Exceptions.

            (l)     To the extent in Seller's possession or control, (i) all
access and security cards to restricted or secured areas of the Property and
(ii) keys to all locks at the Property, all of which may remain on site at the
Property and need not be delivered to the location of the Closing.

            (m)     An Operating Statement for May 2002 if the Closing occurs on
or after June 16, 2002 and the Arrearages Schedule updated to show any changes
from EXHIBIT K and dated no more than one (1) Business Day prior to the Closing
Date.

     SECTION 10.4   PRORATIONS.

            (a)     Seller and Purchaser agree to adjust, as of 11:59 p.m. on
the day preceding the Closing Date (the "PRORATION TIME"), the following
(collectively, the "PRORATION ITEMS"):

                    (i)    Rentals, in accordance with Section 10.4(b) below.

                    (ii)   Cash Security Deposits (to the extent such Security
            Deposits have not yet been applied toward the obligations of any
            Tenant under the Leases) and any prepaid rents, together with
            interest required to be paid to Tenants thereon.

                    (iii)  Utility charges payable by Seller, including,
            without limit.ation, electricity, water charges and sewer charges.
            If there are meters on the Real Property, Seller will cause readings
            of all said meters to be performed not more than three (3) Business
            Days prior to the Closing Date, and a per diem adjustment shall be
            made for the days between the meter reading date and the Closing
            Date based on the most recent meter reading.

                    (iv)   Amounts payable under the Construction Contracts.

                    (v)    Amounts payable under the Spectrasite Agreements
            (unless Purchaser complies with the requirements in Section 3.2).

                    (vi)   Ad valorem taxes due and payable for the calendar
            year. If the Closing Date shall occur before the tax rate is fixed,
            the apportionment of ad valorem taxes shall be upon the basis of the
            tax rate for the preceding year applied to the latest assessed
            valuation. If, subsequent to the Closing Date, ad valorem taxes (by
            reason of change in either assessment or rate or for any other
            reason) for the Real Property and Improvements should be determined
            to be higher or lower than those that are apportioned, a new
            computation shall be made, and Seller agrees to pay Purchaser any
            increase shown by such recomputation and vice versa. Any and all
            expenses incurred or to be incurred in connection with any real
            estate

<Page>

            tax appeals that are pending at the time of Closing shall be
            prorated in the same manner as ad valorem taxes set forth above.

     Seller will be charged and credited for the amounts of all of the Proration
Items relating to the period up to and including the Proration Time, and
Purchaser will be charged and credited for all of the Proration Items relating
to the period after the Proration Time. The estimated Closing prorations shall
be set forth on a preliminary closing statement to be prepared by Seller and
submitted to Purchaser prior to the Closing Date (the "CLOSING STATEMENT"). The
Closing Statement, once agreed upon, shall be signed by Purchaser and Seller.
The proration shall be paid at Closing by Purchaser to Seller (if the prorations
result in a net credit to Seller) or by Seller to Purchaser (if the prorations
result in a net credit to Purchaser) by increasing or reducing the cash to be
delivered by Purchaser in payment of the Purchase Price at the Closing. If the
actual amounts of the Proration Items are not known as of the Closing Date, the
prorations will be made at Closing on the basis of the best evidence then
available; thereafter, when actual figures are received, re-prorations will be
made on the basis of the actual figures, and a final cash settlement will be
made between Seller and Purchaser. No prorations will be made in relation to
insurance premiums, and Seller's insurance policies will not be assigned to
Purchaser. Final readings and final billings for utilities will be made if
possible as of the Closing Date, in which event no proration will be made at the
Closing with respect to utility bills. Seller will be entitled to all deposits
presently in effect with the utility providers, and Purchaser will be obligated
to make its own arrangements for any deposits with the utility providers. The
provisions of this Section 10.4(a) will survive the Closing for twelve (12)
months.

            (b)     Purchaser will receive a credit on the Closing Statement for
all unpaid amounts under the Construction Contracts assumed by Purchaser
hereunder to the extent such amounts relate to incomplete tenant improvements
contemplated by the relevant Lease. Purchaser will also receive a credit on the
Closing Statement for the prorated amount (as of the Proration Time) of all
Rental previously paid to or collected by Seller and attributable to any period
following the Proration Time. After the Closing, Seller will cause to be paid or
turned over to Purchaser all Rental, if any, received by Seller after Closing
and attributable to any period following the Proration Time. "RENTAL" as used
herein includes fixed monthly rentals, additional rentals, percentage rentals,
escalation rentals (which include each Tenant's proportionate share of building
operation and maintenance costs and expenses as provided for under its Lease, to
the extent the same exceeds any expense stop specified in such Lease),
retroactive rentals, all administrative charges, utility charges, tenant or real
property association dues, storage rentals, special event proceeds, temporary
rents, telephone receipts, locker rentals, vending machine receipts and other
sums and charges payable by Tenants under the Leases or from other occupants or
users of the Property. Rental is "DELINQUENT" when it was due prior to the
Closing Date, and payment thereof has not been made on or before the Proration
Time. Delinquent Rental will not be prorated. With respect to Tenants still in
occupancy, Purchaser agrees to use commercially reasonable efforts with respect
to the collection of any Delinquent Rental, but Purchaser will have no liability
for the failure to collect any such amounts and will not be required to pursue
legal action to enforce collection of any such amounts owed to Seller by any
Tenant. With respect to Tenants no longer in occupancy, Seller reserves the
right to pursue

<Page>

the collection of Delinquent Rental. All sums collected by Purchaser from and
after Closing from each Tenant (excluding tenant specific billings for tenant
work orders and other specific services as described in and governed by Section
10.4(d) below) will be applied first to current Rental (which may include
delinquencies owed to Seller for the calendar month of Closing) and then to
delinquencies owed by such Tenant to Seller. Any sums due Seller will be
promptly remitted to Seller.

            (c)     At the Closing, Seller shall deliver to Purchaser a list of
additional rent, however characterized, under each Lease, including without
limitation, real estate taxes, electrical charges, utility costs and operating
expenses (collectively, "OPERATING EXPENSES") billed to Tenants for the calendar
year in which the Closing occurs (both on a monthly basis and in the aggregate),
the basis on which the monthly amounts are being billed and the amounts incurred
by Seller on account of the components of Operating Expenses for such calendar
year. Upon the reconciliation by Purchaser of the Operating Expenses billed to
Tenants, and the amounts actually incurred for such calendar year, Seller and
Purchaser shall be liable for overpayments of Operating Expenses, and shall be
entitled to payments from Tenants with respect to underpayments of Operating
Expenses, as the case may be, on a PRO-RATA basis based upon each party's period
of ownership during such calendar year regardless of when such expenses are
incurred during such calendar year.

            (d)     With respect to specific tenant billings for work orders,
special items performed or provided at the request of a Tenant, excess tenant
improvement costs (including excess tenant improvements costs amortized over the
term of the Lease and paid as additional Rental) or other specific services,
which are collected by Purchaser after the Closing Date but relate to the
foregoing specific services rendered by Seller prior to the Proration Time, then
notwithstanding anything to the contrary contained herein, Purchaser shall cause
the amounts collected from such Tenant that are either specifically designated
by such Tenant as relating to such specific services or that are in an amount
exactly equal to any such billing to be paid to Seller on account thereof.

            (e)     Seller shall credit to Purchaser at Closing the amount of
$229,763.33 to be used by Purchaser for payment toward all costs, including,
without limitation, tenant improvement costs, leasing commissions and other
expenditures, associated with any Lease or any Lease renewal, expansion or other
modification executed by Seller and Tenant or exercised by any Tenant after
April 29, 2002 and prior to the Closing Date, whether such commissions or other
costs are being paid in installments or otherwise, including, without
limitation, such costs associated with those Leases set forth on EXHIBIT T, and
Purchaser shall assume the payment of all of the foregoing costs after Closing;
provided that if any of the costs set forth above in this Section 10.4(e) have
been paid by Seller prior to Closing, the total amount of such costs already
paid by Seller shall be deducted from the $229,763.33 credit referenced above.
If Purchaser acquires the Property, Purchaser shall be responsible for paying
the costs, including, without limitation, tenant improvement costs, leasing
commissions and other expenditures, associated with all Leases and any Lease
renewal, expansion or other modification executed after April 29, 2002.

<Page>

     SECTION 10.5   COSTS OF TITLE COMPANY AND CLOSING COSTS. Costs of the Title
Company and other Closing costs incurred in connection with the Closing will be
allocated as follows:

            (a)     Seller shall pay (i) Seller's attorney's fees; (ii) one-half
(1/2) of escrow fees, if any; and (iii) the cost of the base premium for the
Title Policy and customary title searches; and (iv) the cost of the Updated
Survey up to Two Thousand Dollars ($2,000).

            (b)     Purchaser shall pay (i) the costs of recording the Deed to
the Property and all other documents; (ii) all costs of any additional coverage
under the Title Policy or endorsements or deletions (including, without
limitation, the modification or deletion of the survey exception) to the Title
Policy that are desired by Purchaser; (iii) all premiums and other costs for any
mortgagee policy of title insurance, if any, including but not limited to any
endorsements or deletions; (iv) Purchaser's attorney's fees; (v) one-half (1/2)
of escrow fees, if any and (vi) the cost of the Updated Survey, except to the
extent paid by Seller as set forth in Section 10.5(a).

            (c)     Any other costs and expenses of Closing not provided for in
this Section 10.5 shall be allocated between Purchaser and Seller in accordance
with the custom in the area in which the Property is located.

     SECTION 10.6   POST-CLOSING DELIVERY OF TENANT NOTICE LETTERS. Immediately
following Closing, Purchaser will deliver to each Tenant a Tenant Notice Letter,
as described in Section 10.2(e).

     SECTION 10.7   LIKE-KIND EXCHANGE. Purchaser hereby acknowledges that
Seller may now or hereafter desire to enter into a partially or completely
nontaxable exchange (a "SECTION 1031 EXCHANGE") involving the Property (and/or
any one or more of the properties comprising the Property) under Section 1031 of
the Internal Revenue Code of 1986, as amended, and the Treasury Regulations
promulgated thereunder. In connection therewith, and notwithstanding anything
herein to the contrary, Purchaser shall, at no cost or expense to Purchaser,
cooperate with Seller and shall take, and consent to Seller taking, any
reasonable action in furtherance of effectuating a Section 1031 Exchange
(including, without limitation, any action undertaken pursuant to Revenue
Procedure 2000-37, 2000-40 IRB, as may hereafter be amended or revised (the
"REVENUE PROCEDURE")), including, without limitation, (a) permitting Seller or
an "exchange accommodation titleholder" (within the meaning of the Revenue
Procedure) ("EAT") to assign, or cause the assignment of, this Agreement and all
of Seller's rights hereunder with respect to any or all of the Property to a
"qualified intermediary" (as defined in Treasury Regulations Section
1.1031(k)-1(g)(4)(iii)) (a "QI"); (b) permitting Seller to assign this Agreement
and all of Seller's rights and obligations hereunder with respect to any or all
of the Property and/or to convey, transfer or sell any or all of the Property,
to (i) an EAT; (ii) any one or more limited liability companies ("LLCs") that
are wholly-owned by an EAT; or (iii) any one or more LLCs that are wholly-owned
by Seller and/or any affiliate of Seller and to thereafter permit Seller to
assign its interest in such one or more LLCs to an EAT; and (c) pursuant to the
terms of this Agreement, having any or all of the Property conveyed by an EAT or
any one or more of the

<Page>

LLCs referred to in (b)(ii) or (b)(iii) above, and allowing for the
consideration therefor to be paid by an EAT, any such LLC or a QI; PROVIDED,
HOWEVER, that Purchaser shall not be required to delay the Closing and shall not
incur any additional liability or obligation in connection therewith; and
PROVIDED FURTHER that Seller shall provide whatever safeguards are reasonably
requested by Purchaser, and not inconsistent with Seller's desire to effectuate
a Section 1031 Exchange involving any of the Property, to ensure that all of
Seller's obligations under this Agreement shall be satisfied in accordance with
the terms thereof.

                                   ARTICLE XI
                            CONDEMNATION AND CASUALTY

     SECTION 11.1   CASUALTY. If, prior to the Closing Date, all or a
Significant Portion of the Property is destroyed or damaged by fire or other
casualty, Seller will notify Purchaser of such casualty. Purchaser will have the
option to terminate this Agreement upon notice to Seller given not later than
fifteen (15) days after receipt of Seller's notice. If this Agreement is
terminated under this Section 11.1, the Earnest Money Deposit and all interest
accrued thereon will be returned to Purchaser and thereafter neither Seller nor
Purchaser will have any further rights or obligations to the other hereunder
except with respect to the Termination Surviving Obligations. If Purchaser does
not elect to terminate this Agreement or less than a Significant Portion of the
Property is destroyed or damaged as aforesaid, Seller will not be obligated to
repair such damage or destruction but (a) Seller will assign and turn over to
Purchaser the insurance proceeds net of reasonable collection costs (or if such
have not been awarded, all of its right, title and interest therein) payable
with respect to such fire or other casualty up to the fair market value of the
Property prior to the casualty and (b) the parties will proceed to Closing
pursuant to the terms hereof without abatement of the Purchase Price, except
that Purchaser will receive credit for any insurance deductible amount. In the
event Seller elects to perform any repairs as a result of a casualty, Seller
will be entitled to deduct its costs and expenses from any amount to which
Purchaser is entitled under this Section 11.1, which right shall survive the
Closing.

     SECTION 11.2   CONDEMNATION OF PROPERTY. In the event of (a) any
condemnation or sale in lieu of condemnation of the Property; or (b) any
condemnation or sale in lieu of condemnation of greater than twenty-five percent
(25%) of the fair market value of the Property prior to the Closing, Purchaser
will have the option, to be exercised within fifteen (15) days after receipt of
notice of such condemnation or sale, of (i) terminating this Agreement or (ii)
electing to have this Agreement remain in full force and effect. In the event
that either (x) any condemnation or sale in lieu of condemnation of the Property
is for equal to or less than twenty-five percent (25%) of the fair market value
of the Property, or (y) Purchaser does not terminate this Agreement pursuant to
the preceding sentence, Seller will assign to Purchaser any and all claims for
the proceeds of such condemnation or sale to the extent the same are applicable
to the Property, and Purchaser will take title to the Property with the
assignment of such proceeds and subject to such condemnation and without
reduction of the Purchase Price. Should Purchaser elect to terminate Purchaser's
obligations under this Agreement under the provisions of this Section 11.2, the
Earnest Money Deposit and any interest thereon will be returned to Purchaser and
neither Seller nor Purchaser will have any further obligation under this
Agreement, except for the Termination

<Page>

Surviving Obligations. Notwithstanding anything to the contrary herein, if any
eminent domain or condemnation proceeding is instituted (or notice of same is
given) solely for the taking of any subsurface rights for utility easements or
for any right-of-way easement, and the surface may, after such taking, be used
in substantially the same manner as though such rights have not been taken,
Purchaser will not be entitled to terminate this Agreement, but any award
resulting therefrom will be assigned to Purchaser at Closing and will be the
exclusive property of Purchaser upon Closing.

                                   ARTICLE XII
                                 CONFIDENTIALITY

     SECTION 12.1   CONFIDENTIALITY. Except as hereinafter permitted, Seller and
Purchaser each expressly acknowledge and agree that prior to Closing, the
transactions contemplated by this Agreement and the terms, conditions, and
negotiations concerning the same will be held in the strictest confidence by
each of them and will not be disclosed by either of them except to their
respective legal counsel, accountants, consultants, officers, partners,
directors, shareholders, brokers, lenders, consultants and other Licensee
Parties, and except and only to the extent that such disclosure may be necessary
for their respective performances hereunder. Except as expressly provided in
this Agreement, Purchaser further acknowledges and agrees that, unless and until
the Closing occurs, all information obtained by Purchaser in connection with the
Property will not be disclosed by Purchaser to any third persons without the
prior written consent of Seller. Nothing contained in this Article XII will
preclude or limit either party to this Agreement from issuing a press release or
making other disclosures with respect to any information otherwise deemed
confidential under this Article XII (a) in response to lawful process or
subpoena or other valid or enforceable order of a court of competent
jurisdiction or (b) required by law or (c) required by rule or regulation of the
Securities and Exchange Commission or the New York Stock Exchange, including
without limitation in any filings required by a governmental authority or (d)
with respect to information that has been previously disclosed to the general
public by Seller or Mack-Cali Realty Corporation. In determining whether a
disclosure contemplated in the preceding sentence is required by law or by rule
or regulation of the Securities and Exchange Commission or the New York Stock
Exchange, the disclosing party is entitled to rely upon the written advice of
counsel. Nothing in this Article XII will negate, supersede or otherwise affect
the obligations of the parties under the Confidentiality Agreement, and the
provisions of this Article XII will survive the termination of this Agreement.
Any press release issued by either party to this Agreement after the Closing,
the subject of which is the transaction contemplated by this Agreement (i.e. the
sale of the Property), shall be in the form and substance of the press releases
attached hereto as EXHIBIT S-1 or EXHIBIT S-2, as applicable, provided that each
party's press release is subject to the review by such party's securities
counsel and may be revised if, and to the extent, such counsel advises that a
revision is legally required.

<Page>

                                  ARTICLE XIII
                                    REMEDIES

     SECTION 13.1   DEFAULT BY SELLER. In the event the Closing and the
transactions contemplated hereby do not occur as herein provided by reason of
any default of Seller, Purchaser may, as Purchaser's sole and exclusive remedy,
elect by notice to Seller within thirty (30) days following the Scheduled
Closing Date, either of the following: (a) terminate this Agreement, in which
event Purchaser will receive from the Escrow Agent the Earnest Money Deposit,
together with all interest accrued thereon, plus out of pocket costs and
expenses incurred in connection with this transaction not to exceed $33,333.33,
whereupon Seller and Purchaser will have no further rights or obligations under
this Agreement, except with respect to the Termination Surviving Obligations; or
(b) seek to enforce specific performance of Seller's obligation to execute the
documents required to convey the Property to Purchaser and to remove liens to
the extent required by Section 6.3(b), it being understood and agreed that the
remedy of specific performance shall not be available to enforce any other
obligation of Seller hereunder. Purchaser expressly waives its rights to seek
damages in the event of Seller's default hereunder except for actual damages
incurred by Purchaser due to fraudulent acts of Seller, but in no event shall
Purchaser be entitled to seek speculative, consequential or punitive damages.
Purchaser shall be deemed to have elected to terminate this Agreement and
receive back the Earnest Money Deposit if Purchaser fails to file suit for
specific performance against Seller in a court having jurisdiction in the county
and state in which the Property is located on or before thirty (30) days
following the Scheduled Closing Date. Notwithstanding the foregoing, nothing
contained in this Section 13.1 will limit Purchaser's remedies at law, in equity
or as herein provided in pursuing remedies of a breach by Seller of any of the
Termination Surviving Obligations.

     SECTION 13.2   DEFAULT BY PURCHASER. In the event the Closing and the
consummation of the transactions contemplated herein do not occur as provided
herein by reason of any default of Purchaser, Purchaser and Seller agree it
would be impractical and extremely difficult to fix the damages which Seller may
suffer. Purchaser and Seller hereby agree that (a) an amount equal to the
Earnest Money Deposit, together with all interest accrued thereon, is a
reasonable estimate of the total net detriment Seller would suffer in the event
Purchaser defaults and fails to complete the purchase of the Property, and (b)
such amount will be the full, agreed and liquidated damages for Purchaser's
default and failure to complete the purchase of the Property, and will be
Seller's sole and exclusive remedy (whether at law or in equity) for any default
of Purchaser resulting in the failure of consummation of the Closing, whereupon
this Agreement will terminate and Seller and Purchaser will have no further
rights or obligations hereunder, except with respect to the Termination
Surviving Obligations. The payment of such amount as liquidated damages is not
intended as a forfeiture or penalty but is intended to constitute liquidated
damages to Seller. Notwithstanding the foregoing, nothing contained herein will
limit Seller's remedies at law, in equity or as herein provided in the event of
a breach by Purchaser of any of the Termination Surviving Obligations.

<Page>

                                   ARTICLE XIV
                                     NOTICES

     SECTION 14.1   NOTICES.

            (a)     All notices or other communications required or permitted
hereunder shall be in writing, and shall be given by any nationally recognized
overnight delivery service with proof of delivery, or by facsimile transmission
(provided that such facsimile is confirmed by the sender by expedited delivery
service in the manner previously described), sent to the intended addressee at
the address set forth below, or to such other address or to the attention of
such other person as the addressee will have designated by written notice sent
in accordance herewith. Unless changed in accordance with the preceding
sentence, the addresses for notices given pursuant to this Agreement will be as
follows:

     If to Purchaser:      Parkway Properties LP
                           One Jackson Place
                           188 East Capitol Street, Suite 1000
                           Jackson, Mississippi 32901-2195
                           Attn.:  Mr. David Fowler, Senior Vice President
                           (601) 948-4091 (tele.)
                           (601) 949-4077 (fax)

     with a copy to:       Forman, Perry, Watkins, Krutz & Tardy, PLLC
                           One Jackson Place
                           188 East Capitol Street, Suite 1200
                           Jackson, Mississippi 32901
                           Attn.:  Steven M. Hendrix
                           (601) 960-8600 (tele.)
                           (601) 960-8609 (fax)

     If to Seller:         c/o Mack-Cali Realty Corporation
                           11 Commerce Drive
                           Cranford, New Jersey  07016

                           with separate notices to the attention of:

                           Mr. Mitchell E. Hersh
                           (908) 272-8000 (tele.)
                           (908) 272-0214 (fax)

                           and

                           Roger W. Thomas, Esq.
                           (908) 272-2612 (tele.)
                           (908) 497-0485 (fax)

<Page>

     With a copy to:       Jones, Day, Reavis & Pogue
                           2727 North Harwood Street
                           Dallas, Texas 75201
                           Attn:  David J. Lowery, Esq.
                           (214) 220-3939 (tele.)
                           (214) 969-5100 (fax)

     If to Escrow Agent:   Lawyers Title Insurance Corporation
                           655 Third Avenue, 11th Floor
                           New York, New York 10017
                           Attn:  Mr. Peter Doyle
                           (212) 949-0100 (tele.)
                           (212) 986-3215 (fax)

            (b)     Notices given by (i) overnight delivery service as aforesaid
shall be deemed received and effective on the first (1st) Business Day following
such dispatch and (ii) facsimile transmission as aforesaid shall be deemed given
at the time and on the date of machine transmittal provided same is sent and
confirmation of receipt is received by the sender prior to 4:00 p.m. (EST) on a
Business Day (if sent later, then notice shall be deemed given on the next
Business Day). Notices may be given by counsel for the parties described above,
and such notices shall be deemed given by said party, for all purposes
hereunder.

            (c)     Notwithstanding anything to the contrary in this Section
14.1, if Seller elects to deliver any due diligence materials to Purchaser (as
opposed to making such materials available pursuant to Section 5.2), such due
diligence materials shall be sent to only one addressee, as follows:

                           Mr. David Fowler
                           Parkway Properties LP
                           One Jackson Place
                           188 East Capitol Street, Suite 1000
                           Jackson, Mississippi 32901-2195

                                   ARTICLE XV
                          ASSIGNMENT AND BINDING EFFECT

     SECTION 15.1   ASSIGNMENT: BINDING EFFECT. Purchaser will not have the
right to assign this Agreement except to a wholly owned subsidiary of Purchaser.

                                   ARTICLE XVI
                                    BROKERAGE

     SECTION 16.1   BROKERS. Seller agrees to pay to Eastdil Realty Company,
L.L.C. (the "BROKER") a brokerage commission pursuant to a separate agreement by
and between Seller and Broker. Purchaser and Seller represent that they have not
dealt with any brokers, finders or

<Page>

salesmen, in connection with this transaction other than Broker, and agree to
indemnify, defend and hold each other harmless from and against any and all
loss, cost, damage, liability or expense, including reasonable attorneys' fees,
which either party may sustain, incur or be exposed to by reason of any claim
for fees or commissions made through the other party. The provisions of this
Article XVI will survive any Closing or termination of this Agreement.

                                  ARTICLE XVII
                                  ESCROW AGENT

     SECTION 17.1   ESCROW.

            (a)     Escrow Agent will hold the Earnest Money Deposit in escrow
in an interest-bearing account of the type generally used by Escrow Agent for
the holding of escrow funds until the earlier of (i) the Closing, or (ii) the
termination of this Agreement in accordance with any right hereunder. In the
event Purchaser has not terminated this Agreement by the end of the Evaluation
Period, the Earnest Money Deposit shall be non-refundable to Purchaser, but
shall be credited against the Purchase Price at the Closing. All interest earned
on the Earnest Money Deposit shall be paid to the party entitled to the Earnest
Money Deposit. In the event this Agreement is terminated prior to the expiration
of the Evaluation Period, the Earnest Money Deposit and all interest accrued
thereon will be returned by the Escrow Agent to Purchaser. In the event the
Closing occurs, the Earnest Money Deposit and all interest accrued thereon will
be released to Seller, and Purchaser shall receive a credit against the Purchase
Price in the amount of the Earnest Money Deposit, with the interest. In all
instances, Escrow Agent shall not release the Earnest Money Deposit to either
party until Escrow Agent has been requested by Seller or Purchaser to release
the Earnest Money Deposit and has given the other party five (5) Business Days
to dispute, or consent to, the release of the Earnest Money Deposit, provided
that, if the Closing occurs, the Earnest Money Deposit and interest thereon will
be applied as set forth above on the Closing Date. Purchaser represents that its
tax identification number, for purposes of reporting the interest earnings, is
72-1344324. Seller represents that its tax identification number, for purposes
of reporting the interest earnings, is 74-2863406.

            (b)     Escrow Agent shall not be liable to any party for any act or
omission, except for bad faith, gross negligence or willful misconduct, and the
parties agree to indemnify Escrow Agent and hold Escrow Agent harmless from any
and all claims, damages, losses or expenses arising in connection herewith. The
parties acknowledge that Escrow Agent is acting solely as stakeholder for their
mutual convenience. In the event Escrow Agent receives written notice of a
dispute between the parties with respect to the Earnest Money Deposit and the
interest earned thereon (the "ESCROWED FUNDS"), Escrow Agent shall not be bound
to release and deliver the Escrowed Funds to either party but may either (i)
continue to hold the Escrowed Funds until otherwise directed in a writing signed
by all parties hereto or (ii) deposit the Escrowed Funds with the clerk of any
court of competent jurisdiction. Upon such deposit, Escrow Agent will be
released from all duties and responsibilities hereunder. Escrow Agent shall have
the right to consult with separate counsel of its own choosing (if it deems such
consultation advisable) and

<Page>

shall not be liable for any action taken, suffered or omitted by it in
accordance with the advice of such counsel.

            (c)     Escrow Agent shall not be required to defend any legal
proceeding which may be instituted against it with respect to the Escrowed
Funds, the Property or the subject matter of this Agreement unless requested to
do so by Purchaser or Seller and is indemnified to its satisfaction against the
cost and expense of such defense. Escrow Agent shall not be required to
institute legal proceedings of any kind and shall have no responsibility for the
genuineness or validity of any document or other item deposited with it or the
collectibility of any check delivered in connection with this Agreement. Escrow
Agent shall be fully protected in acting in accordance with any written
instructions given to it hereunder and believed by it to have been signed by the
proper parties.

                                  ARTICLE XVIII
                                  MISCELLANEOUS

     SECTION 18.1   USE OF PROMOTIONAL MATERIALS. After Closing, Purchaser
shall not use or distribute any promotional materials that contain the name or
logo of Seller, Mack-Cali Realty Corporation, M-C Texas Management L.P. or any
affiliates of the foregoing without redacting the name and logo of Seller,
Mack-Cali Realty Corporation, M-C Texas Management L.P. or any affiliates of the
foregoing, as applicable, from such promotional materials. This Section 18.1
will survive Closing without limitation.

     SECTION 18.2   WAIVERS. No waiver of any breach of any covenant or
provisions contained herein will be deemed a waiver of any preceding or
succeeding breach thereof, or of any other covenant or provision contained
herein. No extension of time for performance of any obligation or act will be
deemed an extension of the time for performance of any other obligation or act.

     SECTION 18.3   TIME OF THE ESSENCE. TIME IS OF THE ESSENCE WITH RESPECT TO
ALL TIME PERIODS AND DATES FOR PERFORMANCE SET FORTH IN THIS AGREEMENT.

     SECTION 18.4   RECOVERY OF CERTAIN FEES. In the event a party hereto
files any action or suit against another party hereto by reason of any breach of
any of the covenants, agreements or provisions contained in this Agreement, then
in that event the prevailing party will be entitled to have and recover certain
fees from the other party including all reasonable attorneys' fees and costs
resulting therefrom. For purposes of this Agreement, the term "attorneys' fees"
or "attorneys' fees and costs" shall mean the fees and expenses of counsel to
the parties hereto, which may include printing, photocopying, duplicating and
other expenses, air freight charges, and fees billed for law clerks, paralegals
and other persons not admitted to the bar but performing services under the
supervision of an attorney, and the costs and fees incurred in connection with
the enforcement or collection of any judgment obtained in any such proceeding.
The provisions of this Section 18.4 shall survive the entry of any judgment, and
shall not merge, or be deemed to have merged, into any judgment.

<Page>

     SECTION 18.5   CONSTRUCTION. Headings at the beginning of each Article
and Section are solely for the convenience of the parties and are not a part of
this Agreement. Whenever required by the context of this Agreement, the singular
will include the plural and the masculine will include the feminine and vice
versa. This Agreement will not be construed as if it had been prepared by one of
the parties, but rather as if both parties had prepared the same. All exhibits
and schedules referred to in this Agreement are attached and incorporated by
this reference, and any capitalized term used in any exhibit or schedule which
is not defined in such exhibit or schedule will have the meaning attributable to
such term in the body of this Agreement. In the event the date on which
Purchaser or Seller is required to take any action under the terms of this
Agreement is not a Business Day, the action will be taken on the next succeeding
Business Day.

     SECTION 18.6   COUNTERPARTS. This Agreement may be executed in multiple
counterparts, each of which, when assembled to include an original signature for
each party contemplated to sign this Agreement, will constitute a complete and
fully executed original. All such fully executed original counterparts will
collectively constitute a single agreement.

     SECTION 18.7   SEVERABILITY. If any term or other provision of this
Agreement is invalid, illegal, or incapable of being enforced by any rule of law
or public policy, all of the other conditions and provisions of this Agreement
will nevertheless remain in full force and effect, so long as the economic or
legal substance of the transactions contemplated hereby is not affected in any
adverse manner to either party. Upon such determination that any term or other
provision is invalid, illegal, or incapable of being enforced, the parties
hereto will negotiate in good faith to modify this Agreement so as to reflect
the original intent of the parties as closely as possible in an acceptable
manner to the end that the transactions contemplated hereby are fulfilled to the
extent possible.

     SECTION 18.8   ENTIRE AGREEMENT. This Agreement is the final expression
of, and contains the entire agreement between, the parties with respect to the
subject matter hereof, and supersedes all prior understandings with respect
thereto, including that certain Agreement of Sale and Purchase dated effective
as of May 31, 2002, between Seller and Purchaser pertaining to all of the
Projects (the "ORIGINAL AGREEMENT"). This Agreement may not be modified,
changed, supplemented or terminated, nor may any obligations hereunder be
waived, except by written instrument, signed by the party to be charged or by
its agent duly authorized in writing, or as otherwise expressly permitted
herein.

     SECTION 18.9   GOVERNING LAW. THIS AGREEMENT WILL BE CONSTRUED, PERFORMED
AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE IN WHICH THE PROPERTY IS
LOCATED. SELLER AND PURCHASER HEREBY IRREVOCABLY SUBMIT TO THE JURISDICTION OF
ANY STATE OR FEDERAL COURT SITTING IN THE STATE IN WHICH THE PROPERTY IS LOCATED
IN ANY ACTION OR PROCEEDING ARISING OUT OF OR RELATING TO THIS AGREEMENT AND
HEREBY IRREVOCABLY AGREE THAT ALL CLAIMS IN RESPECT OF SUCH ACTION OR PROCEEDING
SHALL BE HEARD AND DETERMINED IN A STATE OR FEDERAL COURT SITTING IN THE STATE
IN WHICH THE PROPERTY IS LOCATED.

<Page>

     SECTION 18.10  NO RECORDING. The parties hereto agree that neither this
Agreement nor any affidavit or memorandum concerning it will be recorded and any
recording of this Agreement or any such affidavit or memorandum by Purchaser
will be deemed a default by Purchaser hereunder.

     SECTION 18.11  FURTHER ACTIONS. The parties agree to execute such
instructions to the Title Company and such other instruments and to do such
further acts as may be reasonably necessary to carry out the provisions of this
Agreement.

     SECTION 18.12  EXHIBITS.  The following sets forth a list of Exhibits to
the Agreement:

            Exhibit A -    Assignment
            Exhibit B -    Assignment of Leases
            Exhibit C -    Bill of Sale
            Exhibit D -    Legal Description of the Property
            Exhibit E -    Service Contracts
            Exhibit F -    Lease Schedule
            Exhibit G -    Tenant Estoppel
            Exhibit H -    Suits, Proceedings and Violations
            Exhibit I -    Certificate as to Foreign Status
            Exhibit J -    Leasing Commission Agreements
            Exhibit K -    Arrearages
            Exhibit L -    Environmental Reports
            Exhibit M -    Landlord Estoppel
            Exhibit N -    Security Deposits
            Exhibit O -    Construction Contracts
            Exhibit P -    Major Tenants
            Exhibit Q -    Real Estate Tax Assessments
            Exhibit R -    [Intentionally deleted]
            Exhibit S-1 -  Form of Seller's Post-Closing Press Release
            Exhibit S-2 -  Form of Purchaser's Post-Closing Press Release
            Exhibit T      Prospective New Leases

     SECTION 18.13  NO PARTNERSHIP. Notwithstanding anything to the contrary
contained herein, this Agreement shall not be deemed or construed to make the
parties hereto partners or joint venturers, it being the intention of the
parties to merely create the relationship of Seller and Purchaser with respect
to the Property to be conveyed as contemplated hereby.

     SECTION 18.14  LIMITATIONS ON BENEFITS. It is the explicit intention of
Purchaser and Seller that no person or entity other than Purchaser, Seller and
Seller's Affiliates and their permitted successors and assigns is or shall be
entitled to bring any action to enforce any provision of this Agreement against
any of the parties hereto, and the covenants, undertakings and agreements set
forth in this Agreement shall be solely for the benefit of, and shall be
enforceable only by, Purchaser, Seller and Seller's Affiliates or their
respective successors and

<Page>

assigns as permitted hereunder. Except as set forth in this Section 18.14,
nothing contained in this Agreement shall under any circumstances whatsoever be
deemed or construed, or be interpreted, as making any third party (including,
without limitation, Broker) a beneficiary of any term or provision of this
Agreement or any instrument or document delivered pursuant hereto, and Purchaser
and Seller expressly reject any such intent, construction or interpretation of
this Agreement.

     SECTION 18.15  CROSS DEFAULT, ETC. Notwithstanding anything to the
contrary in this Agreement or in the Original Agreement, a default under this
Agreement will constitute a default under the 1717 St. James Agreement and
the Town & Country Agreement, a termination of this Agreement will result in
the termination of the 1717 St. James Agreement and the Town & Country
Agreement, and the Closing on the sale of the Property will occur
simultaneously with the sale of the 1717 St. James Project and the Town &
Country Project. Without abrogating the generality of the preceding sentence,
termination of this Agreement pursuant to any of Sections 5.3(c), 11.1, 11.2,
13.1 or 13.2 of this Agreement will result in a termination of the 1717 St.
James Agreement and the Town & Country Agreement, and extension of the
Closing Date pursuant to any of Sections 6.3(a) or 9.2(b) will result in an
extension of the Closing under the 1717 St. James Agreement and the Town &
Country Agreement for the same amount of time. In addition, the Title
Commitment and the Title Policy will cover all of the Projects.

            [THE REMAINDER OF THIS PAGE IS INTENTIONALLY LEFT BLANK.]

<Page>

     IN WITNESS WHEREOF, Seller and Purchaser have respectively executed this
Agreement as of the Effective Date.

                                   PURCHASER:

                                   PARKWAY PROPERTIES LP

                                   By:    Parkway Properties General Partners,
                                          Inc., its general partner


                                   By:            /s/  David Fowler
                                          -------------------------------------
                                   Name:               David Fowler
                                          -------------------------------------
                                   Title:              Senior Vice President
                                          -------------------------------------


                                   By:            /s/ Thomas C. Maldmey
                                          -------------------------------------
                                   Name:              Thomas C. Maldmey
                                          -------------------------------------
                                   Title:             Senior Vice President
                                          -------------------------------------


                                   SELLER:

                                   MACK-CALI TEXAS PROPERTY L.P.

                                   By:    Mack-Cali Sub XVII, Inc., its general
                                          partner


                                   By:            /s/ Roger W. Thomas
                                          -------------------------------------
                                   Name:              Roger W. Thomas
                                          -------------------------------------
                                   Title:         Executive Vice President
                                          -------------------------------------

<Page>

                                   AS TO SECTIONS 3.3, 4.3 AND ARTICLE XVII
                                   ONLY:

                                   ESCROW AGENT:

                                   LAWYERS TITLE INSURANCE CORPORATION


                                   By:            /s/ Cathy J. Snider
                                          -------------------------------------
                                   Name:              Cathy J. Snider
                                          -------------------------------------
                                   Title:         Assistant Vice President for
                                                      First American
                                          -------------------------------------