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                                                                    EXHIBIT 10.1

                         CONTRIBUTION AND SALE AGREEMENT

        CONTRIBUTION AND SALE AGREEMENT (this "AGREEMENT") dated as of July 2,
2002, between KEYSTONE OPERATING PARTNERSHIP, L.P., a Delaware limited
partnership, having an address at 200 Four Falls Corporate Center, Suite 208,
West Conshohocken, Pennsylvania 19428 ("OWNER") and NOCHA LLC, a New York
limited liability company, having an address c/o JFR Global Investments at 1302
46th Street, Brooklyn, New York 11219 (the "COMPANY").

                                    RECITALS:

        A. Owner is either the fee owner of or is the lessee under a ground
lease with an industrial development agency of the land and buildings and other
improvements thereon set forth on EXHIBIT A annexed hereto (collectively, the
"OWNER CONTRIBUTED PROPERTIES").

        B. Owner also is either the fee owner of or is the lessee under a ground
lease with an industrial development agency of the land and building and other
improvements thereon set forth on EXHIBIT A-1 annexed hereto (the "OWNER SALE
PROPERTY").

        C. American DE/SPE LLC ("SPE 1"), an Affiliate (as defined in
Section 18.01 hereof) of Owner, is either the fee owner of or is the lessee
under a ground lease with an industrial development agency of the land and
buildings and other improvements set forth on EXHIBIT A-2 annexed hereto
(collectively, the "SPE 1 SALE PROPERTIES," and together with the Owner Sale
Property, the "SALE PROPERTIES").

        D. SPE 1, also is either the fee owner of or is the lessee under a
ground lease with an industrial development agency of the land and buildings and
other improvements set forth on EXHIBIT A-3 annexed hereto (collectively, the
"SPE 1 CONTRIBUTED PROPERTIES").

        E. American DE/SPE2 LLC ("SPE 2"), an Affiliate of the Owner, is the fee
owner of the land and buildings and other improvements set forth on EXHIBIT A-4
annexed hereto (collectively, the "SPE 2 CONTRIBUTED PROPERTIES").

        F. American DE/SPE4, L.P. ("SPE 3"), an Affiliate of the Owner, is the
fee owner of the land and buildings and other improvements set forth on EXHIBIT
A-5 annexed hereto (collectively, the "SPE 3 CONTRIBUTED PROPERTY").

        G. Virginia Street Associates, L.P., a Colorado limited partnership and
Affiliate of the Owner ("SPE 4") is the fee owner of the land and buildings and
other improvements set forth on EXHIBIT A-6 annexed hereto (collectively, the
"SPE 4 CONTRIBUTED PROPERTIES" and together with the Owner Contributed
Properties, the SPE 1 Contributed Properties, the SPE 2 Contributed Properties,
the SPE 3 Contributed Property, the "CONTRIBUTED PROPERTIES" and, together with
the Sale Properties, the "PROPERTIES").

        H. The Company has been formed by JFR Global Investments LLC, a New York
limited liability company, for the purpose of acquiring all right, title and
interest in the Properties.

        I. At the Closing (as hereinafter defined), Owner and an Affiliate or
Affiliates of the Company shall enter into that certain Operating Agreement of
the Company annexed hereto as EXHIBIT B (the "OPERATING AGREEMENT").

        J. Owner, shall contribute and cause the SPE Entities to contribute the
Contributed Properties owned by each such entity and Owner shall sell and cause
SPE 1 to sell the Sale Properties owned by each of them to wholly-owned special
purpose entities of the Company, pursuant to the terms of this Agreement and
upon the satisfaction of the conditions to Closing set forth herein.

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        K. At the Closing, Owner and the SPE Entities shall receive a membership
interest in the Company pursuant to the terms of this Agreement and the
Operating Agreement with respect to the contributions of the Contributed
Properties.

        NOW THEREFORE, in consideration of the terms and conditions contained in
this Agreement, the mutual covenants herein contained and other good and
valuable consideration, the mutual receipt and legal sufficiency of which are
hereby acknowledged, Owner and the Company hereby agree as follows:

    Section 1.  CONTRIBUTION AND SALE; DUE DILIGENCE PERIOD

        1.01.   At the Closing:

                (a)     TRANSFER OF CONTRIBUTED PROPERTIES. (i) Owner shall
contribute, assign, transfer and deliver to the Company, and the Company shall
receive from Owner, upon the terms and conditions set forth in this Agreement:
(1) all right, title and interest of Owner in and to the Owner Contributed
Properties; and (2) all right, title and interest of Owner, if any, in and to
the fixtures, equipment and other personal property attached or appurtenant to
the Owner Contributed Properties in exchange for the Owner Contribution
Consideration (as defined in SCHEDULE 2.01(a)), (ii) Owner shall cause SPE 1 to
contribute, assign, transfer and deliver to a newly formed wholly-owned limited
liability company of the Company ("NEW SPE 1"), and New SPE 1 shall receive from
SPE 1, upon the terms and conditions set forth in this Agreement: (1) all right,
title and interest of SPE 1 in and to the SPE 1 Contributed Properties; and (2)
all right, title and interest of SPE 1, if any, in and to the fixtures,
equipment and other personal property attached or appurtenant to the SPE 1
Contributed Properties in exchange for the SPE 1 Contribution Consideration (as
defined in SCHEDULE 2.01(a)), (iii) Owner shall cause SPE 2 to contribute,
assign, transfer and deliver to a newly formed wholly-owned limited liability
company of the Company ("NEW SPE 2"), and New SPE 2 shall receive from Owner,
upon the terms and conditions set forth in this Agreement: (1) all right, title
and interest of SPE 2 in and to the SPE 2 Contributed Properties; and (2) all
right, title and interest of SPE 2, if any, in and to the fixtures, equipment
and other personal property attached or appurtenant to the SPE 2 Contributed
Properties in exchange for the SPE 2 Contribution Consideration (as defined in
SCHEDULE 2.01(a)), (iv) Owner shall cause SPE 3 to contribute, assign, transfer
and deliver to a newly formed wholly-owned limited liability company of the
Company ("NEW SPE 3"), and New SPE 3 shall receive from Owner, upon the terms
and conditions set forth in this Agreement: (1) all right, title and interest of
SPE 3 in and to the SPE 3 Contributed Property; and (2) all right, title and
interest of SPE 3, if any, in and to the fixtures, equipment and other personal
property attached or appurtenant to the SPE 3 Contributed Property in exchange
for the SPE 3 Contribution Consideration (as defined in SCHEDULE 2.01(a)), (v)
Owner shall cause SPE 4 to contribute, assign, transfer and deliver to a newly
formed wholly-owned limited liability company of the Company ("NEW SPE 4"), and
New SPE 4 shall receive from Owner, upon the terms and conditions set forth in
this Agreement: (1) all right, title and interest of SPE 4 in and to the SPE 4
Contributed Properties; and (2) all right, title and interest of SPE 4, if any,
in and to the fixtures, equipment and other personal property attached or
appurtenant to the SPE 4 Contributed Properties in exchange for the SPE 4
Contribution Consideration (as defined in SCHEDULE 2.01(a)). New SPE1, New SPE2,
New SPE3 and New SPE4 are hereinafter collectively referred to as the "NEW SPE
ENTITIES."

                (b)     TRANSFER OF THE SALE PROPERTIES. (i) Owner shall sell,
assign, transfer and deliver to the Company and the Company shall purchase from
Owner, upon the terms and conditions set forth in this Agreement: (1) all right,
title and interest of Owner in and to the Owner Sale Property; and (2) all
right, title and interest of Owner, if any, in and to the fixtures, equipment
and other personal property attached or appurtenant to the Owner Sale Property
in exchange for the Owner Sales Consideration (as defined in Schedule 2.01(b)),
and (ii) Owner shall cause SPE 1 to sell, assign, transfer and deliver to New
SPE 1 and New SPE 1 shall purchase from SPE 1, upon the terms and conditions set

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forth in this Agreement: (1) all right, title and interest of SPE 1 in and to
the SPE 1 Sale Properties; and (2) all right, title and interest of SPE 1, if
any, in and to the fixtures, equipment and other personal property attached or
appurtenant to the SPE Sale Properties in exchange for the SPE 1 Sales
Consideration (as defined in SCHEDULE 2.01(b)).

                (c)     PURCHASE OF EQUITY INTERESTS. An Affiliate of Owner
shall make a capital contribution to the Company in an amount equal to
Twenty-Five Million Dollars ($25,000,000) less the Contributed Equity Value
(hereinafter defined), in exchange for an equity interest in the Company, all as
further described in the Operating Agreement (the "PURCHASED EQUITY VALUE").

        1.02.   Within five (5) days from the date hereof, Owner shall deliver
copies of or make available for inspection by the Company the materials listed
on EXHIBIT "C" annexed hereto (the "REVIEW MATERIALS"). The Review Materials and
all materials, books and records examined by or on behalf of the Company
pursuant to this Agreement shall: (i) be held in strict confidence by the
Company; (ii) not be used for any purpose other than the investigation and
evaluation of the Properties by the Company and its lenders, attorneys, members,
employees, agents, engineers and consultants, investors, mortgage brokers, and
accountants involved or reasonably likely to be involved in this transaction
(collectively, the "AGENTS"); and (iii) not to be disclosed, divulged or
otherwise furnished to any other person or entity prior to the Closing except to
the Agents or as required by law. If this Agreement is terminated for any reason
whatsoever, the Company shall return to Owner all of the Review Materials in the
possession of the Company and the Agents. The provisions of this Section shall
survive the termination of this Agreement.

        1.03.   The Company shall have a period of up to thirty (30) days
commencing on the later of (i) July 10, 2002 and (ii) the giving of the Board
Approval Notice (hereinafter defined) (the "DUE DILIGENCE PERIOD") to perform
its due diligence review of the Properties, including, without limitation,
performing such engineering, environmental, financial and other analyses as the
Company may determine to be necessary in its sole and absolute discretion.
Notwithstanding the foregoing, no soil and/or groundwater sampling shall be
performed unless and until the location, scope and methodology of such sampling
and the environmental consultant selected by the Company to perform such
sampling have all been approved by Owner, which approval shall not be
unreasonably withheld or delayed. Prior to the initial entry onto the Properties
by the Company's engineers and environmental consultants for purposes of
inspection and possible testing, the Company shall deliver to Owner a policy of
commercial liability insurance from each of the Company's engineers and
environmental consultants covering bodily injury, death and property damage and
naming the Owner as an additional insured in the amount of Two Million Dollars
($2,000,000,000) and issued by an insurance company licensed to do business in
the States of New York, Ohio and Pennsylvania and rated A or better by Best's
Insurance Guide. Copies of all environmental and engineering reports prepared by
or on behalf of the Company with respect to the Properties shall be provided
promptly to Owner. With respect to the Company's right to inspect the
Properties, the Company agrees (i) to provide Timothy A. Peterson, Executive
Vice President of Owner, with not less than one (1) business days' telephonic
notice ((484) 530-1888) prior to each inspection (or, if he is not available,
such telephonic Notice shall be given to Stephen J. Butte at (484) 530-1843),
(ii) each inspection shall be performed during normal business hours or at such
other times as Owner and the Company shall mutually agree and all inspections
shall be subject to any limitations on entry contained in the Leases (as
hereinafter defined) and (iii) the Company and its agents, consultants and
representatives shall use all reasonable efforts to minimize any disruption to
the tenants or occupants of the Properties and the operations thereat. Owner (or
its designee) shall have the right, but not the obligation, to accompany the
Company or its agents, consultants and representations during each such
inspection or examination.

        1.04.   Upon the commencement of the Due Diligence Period, (i) the
Company shall order any third party consulting and engineering reports with
respect to the Properties, including any

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appraisal, Phase I environmental and engineering reports; and (ii) Owner shall
submit (a) to the holders (the "ASSUMED DEBT HOLDERS") of the existing mortgages
encumbering certain of the Properties (the "ASSUMED DEBT") written requests for
approval of the assumption of the Assumed Debt and the issuance of a written
statement setting forth the unpaid principal balance, accrued and unpaid
interest and status of the Assumed Debt (the "ASSUMPTION CONSENTS"), (b) to all
tenants of the Properties written requests for Tenant Estoppels (hereinafter
defined); and (c) requests to the IDA Agencies for the IDA Approvals and IDA
Estoppels (both as hereinafter defined).

        1.05.   Except as otherwise provided herein, the Company's obligations
under this Agreement shall be contingent, only during the Due Diligence Period,
upon the Company being satisfied in its sole discretion with the results of its
due diligence review of the Properties and the Review Materials (the "DUE
DILIGENCE CONDITION"). In the event that the Due Diligence Condition is
satisfied, the Company shall notify Owner and Escrowee (hereinafter defined) in
writing (the "APPROVAL NOTICE") prior to the expiration of the Due Diligence
Period. If the Company shall fail to give the Approval Notice to Owner prior to
the expiration of the Due Diligence Period, the Initial Deposit (hereinafter
defined) and all interest earned thereon shall be promptly returned by Escrowee
to the Company without further notice to Owner, this Agreement shall be
terminated and neither Owner nor the Company shall have any further liability to
the other hereunder, except with respect to the covenants and indemnities
contained in SECTIONS 1.02, 15 and 19 (the "SURVIVING OBLIGATIONS").

    Section 2.  CONTRIBUTION CONSIDERATION AND SALES CONSIDERATION; DEPOSIT OF
                EARNEST MONEY; ACCEPTABLE FUNDS

        2.01.   (a) DETERMINATION AND ALLOCATION OF CONTRIBUTION CONSIDERATION.
SCHEDULE 2.01(a) annexed hereto sets forth (i) the aggregate agreed upon net
equity value for the contribution and transfer of the Contributed Properties
(the "CONTRIBUTED EQUITY VALUE"), (ii) the aggregate contribution consideration
consisting of the Contributed Equity Value and assumption of indebtedness with
respect to the Contributed Properties (the "CONTRIBUTION CONSIDERATION") and
(iii) the allocation of such aggregate contribution consideration among the
Owner Contribution Consideration, the SPE 1 Contribution Consideration, the SPE
2 Contribution Consideration, the SPE 3 Contribution Consideration, the SPE 4
Contribution Consideration, and among the Properties transferred for such
Contribution Consideration. The amounts set forth in SCHEDULE 2.01(a) shall be
adjusted as of the Closing to reflect any principal payments made on the Assumed
Debt after June 1, 2002, it being understood that any such principal payments
shall result in a corresponding increase in the Contributed Equity Value.

                (b) DETERMINATION AND ALLOCATION OF SALES CONSIDERATION.
SCHEDULE 2.01(b) annexed hereto sets forth (i) the aggregate agreed upon net
equity value for the sale and transfer of the Sale Properties to the Company at
the Closing (the "CASH PORTION OF THE SALES PRICE"), (ii) the aggregate sale
consideration consisting of the Cash Portion of the Sales Price and the
assumption of indebtedness with respect to the Sale Properties (the "AGGREGATE
SALES PRICE") and (iii) the allocation of such aggregate sale consideration
among the Owner Sales Consideration and the SPE 1 Sales Consideration with
respect to the Sale Properties. The amounts set forth in SCHEDULE 2.01(b) shall
be adjusted as of the Closing to reflect any principal payments made on the
Assumed Debt after June 1, 2002, it being understood that any such principal
payments shall result in a corresponding increase in the Cash Portion of the
Sales Price.

                (c) SUMMARY OF TOTAL CONSIDERATION. For purposes of convenience
it is understood that, as of the date of this Agreement, the aggregate of the
Contribution Consideration and the Aggregate Sales Price is set forth on
SCHEDULE 2.01(c) and the aggregate of the Contributed Equity Value and the
Purchase Equity Value (collectively, the "TOTAL EQUITY INTEREST") is also set
forth on SCHEDULE 2.01(c).

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        2.02.   (a) Contemporaneously with the execution and delivery of this
Agreement, the Company shall pay a good faith deposit in the amount of One
Million and 00/100 Dollars ($1,000,000.00) (the "INITIAL DEPOSIT") to Fidelity
National Title Insurance Company of New York ("ESCROWEE"), at its New York City
office, in its capacity as escrow agent. No provision of this Agreement shall be
binding upon Owner unless and until Escrowee shall have received the Initial
Deposit. Within one (1) business day after the giving of the Approval Notice
(the "ADDITIONAL DEPOSIT PAYMENT PERIOD"), the Company shall pay to Escrowee the
additional amount of Two Million and 00/100 Dollars ($2,000,000.00) (the
"ADDITIONAL DEPOSIT"). If the Additional Deposit is not paid prior to the
expiration of the Additional Deposit Payment Period (time being of the essence),
the Initial Deposit and all interest earned thereon shall be promptly returned
by Escrowee to the Company, this Agreement shall be terminated and neither the
Company nor Owner have any further liability to the other hereunder, except for
the Surviving Obligations. Escrowee shall give prompt written confirmation to
Owner of Escrowee's receipt of the Initial Deposit and the Additional Deposit.
The Initial Deposit and the Additional Deposit, including all interest earned
thereon, are hereinafter collectively referred to as the "EARNEST MONEY."

                (b) Escrowee shall hold the Earnest Money deposited by the
Company in escrow until Closing or sooner termination of this Agreement and
shall pay over or apply the Earnest Money in accordance with the terms of
SECTION 1.05 and this SECTION 2.02. Escrowee shall hold the Earnest Money in an
interest-bearing account for the benefit of the parties. Accrued interest on the
Earnest Money shall be paid to the party entitled to the Earnest Money pursuant
to this Agreement and the party receiving the interest shall pay any income
taxes thereon. The Social Security or Federal Identification numbers of the
parties shall be furnished to Escrowee upon request. At Closing, the Earnest
Money shall be paid by Escrowee to Owner. Except as set forth in SECTION 1.05,
if for any reason Closing does not occur and either party gives written notice
to Escrowee demanding payment of the Earnest Money, Escrowee shall give prompt
written notice to the other party of such demand. If Escrowee does not receive
written notice of objection from such other party to the proposed payment within
10 business days after the giving of such written notice, Escrowee is hereby
authorized and directed to make such payment. If Escrowee does receive such
written notice of objection within such 10 day period or if for any other reason
Escrowee in good faith shall elect not to make such payment, Escrowee shall
continue to hold such amount until otherwise directed by written notice from the
parties to this Agreement or a final, nonappealable judgment, order or decree of
court. However, Escrowee shall have the right at any time to deposit the Earnest
Money with the clerk of the Supreme Court of the State of New York, New York
County and shall give written notice of such deposit to Owner and the Company.
Upon such deposit or other disbursement in accordance with the terms of this
SECTION 2.02, Escrowee shall be relieved and discharged of all further
obligations and responsibilities hereunder.

                        (i)     The parties acknowledge that, although Escrowee
is holding the Earnest Money for the parties' account, for all other purposes
Escrowee is acting solely as a stakeholder at their request and for their
convenience and that Escrowee shall not be liable to either party for any act or
omission on its part unless taken or suffered in bad faith or in willful
disregard of this Agreement or involving gross negligence on the part of
Escrowee. Owner and the Company jointly and severally agree to defend, indemnify
and hold Escrowee harmless from and against all costs, claims and expenses
(including reasonable attorneys' fees) incurred in connection with the
performance of Escrowee's duties hereunder, except with respect to actions or
omissions taken or suffered by Escrowee in bad faith or in willful disregard of
this Agreement or involving gross negligence on the part of Escrowee.

                        (ii)    Escrowee may act or refrain from acting in
respect of any matter referred to herein in full reliance upon and with the
advice of legal counsel which may be selected by it and shall be fully protected
in so acting or refraining from action upon the advice of such counsel.

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                        (iii)   Escrowee acknowledges Escrowee's agreement to
the provisions of this SECTION 2.02 by signing in the place indicated in this
Agreement.

        2.03.   At the Closing, the Company shall pay the Cash Portion of the
Sales Price (plus or minus net adjustments and prorations applied to the Sale
Properties pursuant to SECTION 13) to Owner and SPE 1.

        2.04.   Immediately after the Closing, Owner and the SPE Entities shall
take all necessary steps to cause those equity interests in the Company
attributable to the SPE Entities as a result of the contributions described
herein to be transferred to Owner.

        2.05.   All cash monies payable by the Company to Owner under this
Agreement, unless otherwise specified in this Agreement, shall be paid by
Federal funds wire transfer of immediately available funds to an account
designated by Owner.

        2.06.   Owner and SPE 1 have advised the Company, and the Company hereby
acknowledges, that Owner and SPE 1 each intend to enter into a separate exchange
agreement and other related agreements with a qualified "Intermediary" in order
to effect the transfer of the Owner Sale Property and the SPE 1 Sale Properties,
respectively, and the acquisition by Owner and SPE 1 of certain "Replacement
Properties" as a like-kind exchange in accordance with the provisions of
Section 1031 of the Internal Revenue Code of 1986, as amended, and the Treasury
Regulations promulgated thereunder. In furtherance of the foregoing: (a) Owner
and SPE 1 shall have the right to assign all of its right, title and interest in
and to this Agreement with respect to the Owner Sale Property and the SPE 1 Sale
Properties, respectively, to the selected Intermediary (but Owner and SPE 1
shall each remain obligated for all of its agreements and other undertakings
hereunder), and (b) at the request of Owner or SPE 1 from time to time, the
Company will reasonably cooperate with Owner or SPE 1 and with the selected
Intermediary in order to effect the intended like-kind exchanges contemplated by
the foregoing. Owner shall pay all reasonable out-of-pocket expenses incurred by
the Company in cooperating with Owner to effectuate the like-kind exchanges
described above and shall indemnify, defend and hold the Company harmless from
and against all claims, costs, expenses and damages (including, without
limitation, attorneys' fees) resulting or arising from such like-kind exchanges.

        2.07.   The Company has advised Owner, and Owner hereby acknowledges,
that the Company may enter into separate exchange agreements with Affiliates of
the Company affecting up to three (3) of the Properties, in accordance with the
exchange structure described in Section 2.06. Owner agrees to reasonably
cooperate with the Company and the selected Intermediary in order to effectuate
such like-kind exchanges, provided that (i) the Company shall pay all reasonable
out-of-pocket expenses incurred by Owner in cooperating with the Company to
effectuate such like-kind exchanges and shall indemnify, defend and hold Owner
harmless from and against all claims, costs, expenses and damages (including,
without limitation, attorneys' fees) resulting or arising from such like-kind
exchanges and (ii) at the conclusion of each such like-kind exchange, Owner
shall be in the same position as it would have been (considering such factors as
economic terms, governing documents, potential liability and nature and extent
of risk) if such like-kind exchange had not been effectuated.

    Section 3.  THE CLOSING

        3.01.   Except as otherwise provided in this Agreement, the closing of
title hereunder ("CLOSING") shall take place at 10:00 a.m. on the date (the
"CLOSING DATE") that is the later of (a) seven (7) business days after the date
of receipt of all of the Assumption Consents and IDA Approvals or (b) the
thirtieth (30th) day following the expiration of the Due Diligence Period, at
the offices of Clifford Chance Rogers & Wells LLP, 200 Park Avenue, New York,
New York 10166, or such other location as the

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parties may agree upon; provided, however, that if the Closing has not occurred
by the sixtieth (60th) day following the expiration of the Due Diligence Period
(the "CLOSING DEADLINE"), either Owner or the Company may elect, at its option,
to terminate this Agreement by giving the other party written notice of the
exercise of such election at any time after the Closing Deadline, whereupon this
Agreement shall terminate, the Earnest Money shall be refunded to the Company
and neither Owner nor the Company shall have any further liability to the other
hereunder, except for the Surviving Obligations. All cash monies payable by the
Company to Owner pursuant to this Agreement, unless otherwise specified in this
Agreement, shall be paid by federal funds wire transfer of immediate available
funds.

    Section 4.  REPRESENTATIONS AND WARRANTIES

        4.01.   Subject to SECTIONS 5.01 and 5.02 hereof, Owner represents and
warrants to the Company as follows:

                (a) Owner is a limited partnership, organized, existing and in
good standing under the laws of the State of Delaware, is qualified and in good
standing in the states in which each of the Properties directly owned by it are
located and has the requisite power and authority to enter into and perform the
terms of this Agreement. With respect to the SPE Entities: (i) SPE 1 is a
limited liability company, organized, existing and in good standing under the
laws of the State of Delaware, and is qualified and in good standing in the
States of New York and Ohio; (ii) SPE 2 is a limited liability company,
organized, existing and in good standing under the laws of the State of
Delaware, and is qualified and in good standing in the State of New York; (iii)
SPE 3 is a limited partnership, organized, existing and in good standing under
the laws of the State of Delaware and is qualified and in good standing in the
Commonwealth of Pennsylvania; and (iv) SPE 4 is a limited partnership,
organized, existing and in good standing under the laws of the State of
Colorado, and is qualified and in good standing in the States of New York and
Pennsylvania.

                (b) Except for the Assumption Consents and the IDA Approvals,
and subject to SECTION 10.04 hereof, the execution and delivery of this
Agreement and the consummation of the transactions contemplated hereby on the
part of Owner have been duly authorized by all necessary parties and no other
proceedings on the part of Owner are necessary in order to permit it to
consummate the transactions contemplated hereby.

                (c) This Agreement has been duly executed by Owner and all of
Owner's obligations hereunder are the legal, valid and binding obligations of
Owner, enforceable in accordance with the terms of this Agreement.

                (d) Subject to obtaining the Assumption Consents and the IDA
Approvals, Owner's performance of its duties under this Agreement will not
conflict with, result in a breach of or be a default under, or be adversely
affected by, any existing agreements, instruments, judgments or decrees to which
Owner is a party or by which it or its assets are bound.

                (e) None of Owner, Keystone Property Trust, a Maryland real
estate investment trust (the "REIT"), or the SPE Entities is the subject of any
bankruptcy, reorganization, insolvency or similar proceedings on the date
hereof.

                (f) Except as set forth on EXHIBIT D attached hereto, Owner
warrants that (a) Owner has not received any written notifications, notices of
restrictions or stipulations (which remain outstanding) from the United States
of America, the States wherein the Properties are located or any political
subdivision or agency thereof either requiring any work to be done at the
Properties (the cost of which, individually or in the aggregate, would exceed
$150,000) or threatening to adversely restrict on a

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permanent basis the continued use of or access to the Properties, (b) there are
no pending or, to Owner's knowledge, threatened condemnation proceedings
affecting all or any material portion of any of the Properties or any material
means of ingress and egress to any of the Properties, (c) Owner has not received
any written notifications (which remain outstanding) from any governmental
authority having jurisdiction over the Properties stating that any of the
Properties violates in any material respect any zoning, land use and other
similar laws, orders, ordinances, rules and regulations applicable thereto, and
(d) Owner and the SPE Entities have obtained all material licenses, permits,
certificates of occupancy and other approvals required of Owner and the SPE
Entities to continue the existing operation of the Properties. "OWNER'S
KNOWLEDGE" shall be defined for purposes of this Agreement as the current actual
awareness of Robert F. Savage, Jr., Timothy A. Peterson and Stephen J. Butte in
their respective capacities as Executive Vice President and Chief Operating
Officer, Executive Vice President and Senior Vice President of Asset Management
of Owner (Messrs. Savage and Butte being the management level employees of Owner
and the SPE Entities having responsibility for the day to day oversight of the
management and operation of the Properties).

                (g) Annexed hereto, collectively, as EXHIBIT E are certified
rent rolls for the Properties (the "RENT ROLLS") identifying and listing in
detail, as of the date thereof, by tenant and vacant area, as applicable,
tenants, square footage, monthly fixed rent, monthly estimates for operating
expense and common area maintenance contributions, security deposits, tenant
arrearages, tenants who have been given written notices of default (which remain
outstanding), rent commencement and expiration dates, and renewal and extension
options. To Owner's knowledge, the information concerning written leases (which
together with all existing amendments and modifications thereof are collectively
referred to as "LEASES") set forth in EXHIBIT E annexed hereto is accurate in
all material respects as of the date thereof. Owner has not given, nor has Owner
received, any written notice of a material default (which remains outstanding)
under any of the Leases (the foregoing does not apply to delinquencies in the
payment of monthly rent that have existed for less than thirty (30) days),
except as set forth in the Rent Rolls.

                (h) In addition to the Review Materials, Owner will give or
otherwise will make available to the Company for examination all existing
material contracts, agreements and written notices from governmental authorities
with respect to the Properties, to the extent in Owner's possession or subject
to its control.

                (i) EXHIBIT F annexed hereto (the "INSURANCE SCHEDULE"), lists
all insurance policies obtained by Owner and presently affording coverage with
respect to the Properties.

                (j) Except for the employees set forth on EXHIBIT G annexed
hereto (the "EMPLOYEES"), (i) Owner does not have any employees at the
Properties, (ii) there are no pension plan liabilities, funded or unfunded, with
respect to the Employees, (iii) the Employees are not covered by a collective
bargaining agreement and (iv) following the Closing, the Company shall not be
obligated to employ or continue to employ the Employees.

                (k) EXHIBIT H annexed hereto (the "SERVICE CONTRACT SCHEDULE")
lists all service, maintenance, supply and management contracts affecting the
Properties ("SERVICE CONTRACTS") which are not terminable upon 30 days or less
written notice without penalty. The information set forth therein is accurate as
of the date hereof. Owner has not given, nor has Owner received, any written
notice of a material default (which remains outstanding) under any of the
Service Contracts.

                (l) Neither Owner nor any SPE Entity is a "foreign person" as
defined in the Internal Revenue Code Section 1445, as amended (the "CODE
WITHHOLDING SECTION").

                                        8
<Page>

                (m) Except as set forth on EXHIBIT I annexed hereto, there is no
litigation, arbitration or other adversarial contest or proceeding pending or,
to Owner's knowledge, threatened in writing against Owner or any of the SPE
Entities with respect to any of the Properties (i) which, if adversely decided,
would result in money damages in excess of $75,000 per claim payable by Owner or
any of the SPE Entities (other than claims for personal injury, bodily injury or
property damage which are reasonably believed by Owner to be covered by existing
insurance policies maintained by Owner and/or the SPE Entities), (ii) would
impose any restrictions on the continued use and operation of the Properties as
presently used and operated, (iii) require the performance of any remedial work
or improvements or (iv) would prevent, hinder or delay the consummation of this
transaction.

                (n) The only existing written agreements for the payment of
leasing commissions by the party holding the interest of landlord with respect
to the Properties are those listed on EXHIBIT J annexed hereto (such agreements
are collectively referred to as the "BROKERAGE AGREEMENTS"). EXHIBIT K annexed
hereto sets forth a list of all (i) leasing commissions which have been earned
and are payable under the Brokerage Agreements prior to the date of this
Agreement which have not been paid and (ii) any leasing commissions already
earned under the Brokerage Agreements and which are payable in one or more
installments after the date of this Agreement and with respect to which not all
installments have been paid. EXHIBIT J also sets forth all leasing commissions
that may first become due under the Leases following the Closing. EXHIBIT L sets
forth all outstanding tenant improvement obligations of the landlord under the
Leases (excluding maintenance and repair obligations).

                (o) Except as disclosed in the reports listed on EXHIBIT M
annexed hereto (the "ENVIRONMENTAL REPORTS"), to Owner's knowledge, (i) there
are no underground storage tanks situated at any of the Properties, (ii) there
has not been any release, emission, discharge or disposal of any reportable
quantities of hazardous materials, hazardous substances, contaminants or
pollutants at or from any of the Properties in violation of any environmental
laws and regulations applicable to the Properties, (iii) Owner has not received
any written notification (which remains outstanding from any governmental
authority having jurisdiction over the Properties stating that any hazardous
materials, hazardous substances, contaminants or pollutants have been stored,
generated, disposed of, released or transported at, on or from the Properties in
violation of any environmental laws and regulations applicable to the
Properties, and there is no claim pending against Owner with respect to any such
violation applicable to the Properties and (iv) the Properties have not been
used for the production or generation of hazardous materials, hazardous
substances, contaminants or pollutants, in violation of any environmental laws
and regulations applicable to the Properties.

                (p) Each IDA Lease and Pilot Agreement (both as hereinafter
defined) is in full force and effect. Neither Owner nor any SPE Entity has
given, nor has Owner or any SPE Entity received, any written notice (which
remains outstanding) of a default under any IDA Lease or Pilot Agreement.

                (q) The outstanding principal balances of the Assumed Debt, as
of June 1, 2002, are set forth in SCHEDULE 4.01(q) annexed hereto. Neither Owner
nor any SPE Entity has received any written notice (which remains outstanding)
of a default by the borrower under any of the documents evidencing or securing
the Assumed Debt. To Owner's knowledge, SCHEDULE 4.01(q) sets forth a true and
complete list of all escrow deposits maintained, as of June 1, 2002, under the
documents evidencing or securing the Assumed Debt. All payments of principal and
interest required to have been made by the borrower(s) under the Assumed Debt,
as of June 1, 2002, have been made.

                (r) All copies of the Leases, Service Contracts and Review
Materials furnished by Owner to the Company are true and complete copies (in all
material respects) of those in Owner's possession or subject to its control.

                                        9
<Page>

        4.02.   The Company represents and warrants to Owner as follows:

                (a) The Company is a limited liability company, organized,
existing and in good standing under the laws of the State of New York, at
Closing will be qualified and in good standing in each state in which the
Properties are located and has the requisite power and authority to enter into
and perform the terms of this Agreement.

                (b) The execution and delivery of this Agreement and the
consummation of the transactions contemplated hereby on the part of the Company
have been duly authorized by all necessary parties and no other proceedings on
the part of the Company are necessary in order to permit it to consummate the
transactions contemplated hereby.

                (c) This Agreement has been duly executed by the Company and all
of the Company's obligations hereunder are the legal, valid and binding
obligations of the Company, enforceable in accordance with the terms of this
Agreement.

                (d) The Company's performance of its duties under this Agreement
will not conflict with, result in a breach of or be a default under, or be
adversely affected by, any agreements, instruments, judgments or decrees to
which the Company is a party or by which it or its assets are bound.

                (e) The Company is not the subject of any bankruptcy,
reorganization, insolvency or similar proceedings.

        4.03.   Owner and the Company agree that (a) the Company shall not make
any claim on account of a breach of Owner's representations and warranties
contained in this Agreement and in any document executed by Owner pursuant to
this Agreement (collectively, "OWNER'S REPRESENTATIONS"), unless the aggregate
measure of such claims exceeds $200,000 and (b) Owner's aggregate liability for
claims on account of a breach of Owner's Representations shall not exceed
$4,000,000. The Company shall provide actual written notice to Owner of any
breach of Owner's Representations and shall allow Owner 30 days within which to
cure such breach, or, if such breach cannot reasonably be cured within 30 days,
an additional reasonable time period (not to exceed 60 days), so long as such
cure has been commenced within such 30 days and thereafter diligently pursued.
If Owner fails to cure such breach after actual written notice and within such
cure period, the Company's sole remedy shall be an action at law for damages
actually incurred by the Company as a consequence thereof (excluding therefrom
consequential or punitive damages), which must be commenced, if at all, within
the Limitation Period (as defined in SECTION 17 hereof).

    Section 5.  ACKNOWLEDGMENTS OF THE COMPANY

        5.01.   The Company acknowledges that except as expressly set forth in
this Agreement, neither Owner nor any agent or representative or purported agent
or representative of Owner has made, and Owner is not liable for or bound in any
manner by, any express or implied warranties, guaranties, promises, statements,
inducements, representations or information (including, without limitation, any
information set forth in offering materials heretofore furnished to the Company)
pertaining to the Properties or any part thereof, the physical condition
thereof, environmental matters, income, expenses or operation thereof or the
uses which can be lawfully made of the same under applicable zoning or other
laws or any other matter or thing with respect thereto, including, without
limitation, any existing or prospective leases, operating agreements or other
agreements. Without limiting the foregoing, the Company acknowledges and agrees
that, except as expressly set forth in this Agreement, Owner is not liable for
or bound by (and the Company has not relied upon) any verbal or written
statements, representations, real estate brokers' "set-ups" or offering
materials or any other information respecting the

                                       10
<Page>

Properties furnished by Owner or any broker, employee, agent, consultant or
other person representing or purportedly representing Owner. Accordingly, Owner
is entering into this Agreement based upon the Company's assurances that the
Company has a well-informed opinion of the value of the Properties. The Company
is not relying upon any representations made by Owner regarding market
conditions which influence the Properties such as competitive position relative
to its existing and potential future competitors, market rental rates achievable
at the Properties, vacancy assumptions, credit loss and downtime reserves,
project growth rates (if any) in rents or expenses, impact of the contribution
and sale on assessed values, tenant work and leasing fee levels necessary to
generate estimated market rents, tenant retention ratios and the need for an
amount of any "capital reserves". The provisions of this SECTION 5.01 shall
survive the Closing.

        5.02.   Subject to the Company's rights to perform further due diligence
and to exercise its election to terminate this Agreement as more particularly
set forth in SECTIONS 1.03 AND 1.05 hereof, the Company acknowledges that it has
inspected the Properties, the physical and environmental condition and the uses
thereof and the fixtures, equipment and personal property included in this
contribution and acquisition to its satisfaction, that it has independently
investigated, analyzed and appraised the value and profitability thereof, the
creditworthiness of tenants and the presence of hazardous materials, if any, in
or on the Properties, that it has received or is to receive or have made
available to it by Owner within five (5) days from the date hereof copies of
and/or has reviewed the Leases, the Service Contracts, other agreements and all
other documents referred to herein, that it is thoroughly acquainted with all of
the foregoing and that the Company, in entering into this Agreement, will rely
exclusively upon its own independent investigations, analyses, studies and
appraisals and not upon any information provided to the Company by or on behalf
of Owner with respect thereto. At the Closing, the Company agrees to accept the
Properties in "as is, where is" condition, EXCEPT FOR Owner's representations,
warranties or covenants expressly contained in this Agreement, with all faults
as of the date hereof and specifically and without any warranties,
representations or guarantees, either express or implied as to (i) the
condition, fitness for any particular purpose, or merchantability of the
Properties, (ii) the structural integrity of the Properties, (iii) the accuracy
or completeness of any information, data, materials or conclusions contained in
any information provided to the Company from any source whatsoever, except as
otherwise expressly provided herein, (iv) environmental matters pertaining to
the Properties except as set forth herein, or (v) any other warranty of any
kind, nature or type whatsoever from Owner, except as may be expressly provided
herein, reasonable wear and tear and damage by fire or other casualty (subject
to the provisions of SECTION 8.01 below) between the date hereof and the Closing
Date excepted, and the Company shall assume the risk that adverse matters,
including but not limited to, construction defects and adverse physical and
environmental conditions may not have been revealed by the Company's
investigations; and, except as specifically set forth otherwise in this
Agreement, the Company, upon Closing, shall be deemed to have waived,
relinquished and released Owner from and against any and all claims, demands,
causes of action, losses, damages, liabilities, costs and expenses (including,
attorneys' fees and court costs) of any and every kind or character, known or
unknown, which the Company might have asserted or alleged against Owner and by
reason of or arising out of any latent or patent construction defects or
physical conditions, violations of applicable laws (including, without
limitation, environmental laws) and any and all other acts, omissions, events,
circumstances or matters with respect to the Properties.

    Section 6.  OWNER'S OBLIGATIONS AS TO THE PROPERTIES

        6.01.   Prior to the Closing, Owner agrees that it shall maintain,
repair, manage and operate the Properties in substantially the same manner as
Owner has operated, managed, maintained and repaired the Properties prior to the
date of this Agreement. Owner agrees that Owner (a) will not dissipate the
Properties or remove any material assets, fixtures, equipment or personal
property therefrom (not including any of the foregoing items to the extent owned
by tenants or other occupants of the Properties) unless the same are replaced
with similar items of at least equal quality prior to the Closing,

                                       11
<Page>

(b) will not modify, amend, extend, renew or terminate any Service Contract
which is not terminable upon 30 days or less written notice without a penalty
(each, a "MATERIAL SERVICE CONTRACT") or enter into any new Material Service
Contract (except as set forth in SECTION 6.02 hereof), without the prior consent
of the Company, which consent shall not be unreasonably withheld, conditioned or
delayed and (c) except in compliance with the leasing guidelines contained in
EXHIBIT O annexed hereto, will not amend any Lease in any material respect, or
execute any new or renewal lease, license or other agreement affecting the
ownership or operation of all or any portion of the Properties, without the
prior consent of the Company, which consent shall not be unreasonably withheld,
conditioned or delayed. Any Lease or Material Service Contract submitted by
Owner to the Company for approval and not objected to in a writing given by the
Company to Owner within three (3) business days after the Company's receipt
thereof, shall be deemed approved by the Company. In addition, Owner agrees
that, prior to the Closing, it shall not voluntarily prepay any of the Assumed
Debt or modify, amend or terminate any of the documents evidencing or securing
the Assumed Debt or any of the IDA Leases or the Pilot Agreements, without the
prior consent of the Company, which consent shall not be unreasonably withheld
or delayed.

        6.02.   Notwithstanding anything to the contrary in Section 6.01, prior
to the Closing, Owner may, without the Company's prior consent, terminate or
modify any Lease or Material Service Contract by reason of a default by the
tenant or service provider beyond the expiration of any applicable grace or cure
period in the payment of rent or Additional Rent (as hereinafter defined) or the
provision of services. Any such termination by Owner prior to the Closing shall
not affect the obligations of the Company under this Agreement in any manner or
entitle the Company to an abatement of or credit against the Initial
Distribution or give rise to any other claim on the part of the Company.

        6.03.   Owner shall maintain in full force and effect and use all
commercially reasonable efforts to continue until the Closing the insurance
policies described in the Insurance Schedule annexed hereto and shall use all
commercially reasonable efforts to renew those expiring before the Closing for
no more than one year.

        6.04.   Prior to and as a condition to the Closing (which condition may
be waived, in whole or part, by the Company), Owner shall use all commercially
reasonable efforts in good faith to provide to the Company (a) estoppel
certificates ("TENANT ESTOPPELS") in the form of EXHIBIT T annexed hereto (the
"ESTOPPEL CERTIFICATE FORM") from (A) those tenants under the Leases set forth
on SCHEDULE 6.04 (the "MAJOR TENANTS") and (B) from such other tenants necessary
to obtain, together with Tenant Estoppels from the Major Tenants, at least 85%
of total fixed or base rent paid under such Leases (provided, that, if Owner is
unable to obtain the Tenant Estoppels described in clauses (A) and (B) above,
Owner may deliver to the Company at the Closing substitute estoppel certificates
signed by Owner (each an "OWNER ESTOPPEL") representing up to 10% of the total
fixed or base rent under all Leases (except that no more than two (2) of the
Major Tenants may be covered by an Owner Estoppel), and the Company shall accept
in lieu of such Tenant Estoppel signed by the tenants such Owner Estoppels)),
(ii) from each lessor under a ground lease or superior lease, if any, (iii) from
each party (other than Owner) to any reciprocal easement agreement or other
agreement that materially benefits or burdens the Properties, or portion
thereof, and (iv) from any other tenant under the Leases reasonably required by
Lender or any Assumed Debt Holder and containing such additional or different
provisions as may be required by Lender or any Assumed Debt Holder, provided the
same do not impose any additional obligations or costs on Owner, (b) Assumption
Consents from all of the Assumed Debt Holders and (c) IDA Approvals from the IDA
Agencies. In the event that a tenant under a Lease provides the Company with a
Tenant Estoppel for which Owner has given the Company an Owner Estoppel, the
Company shall retain and rely on such Tenant Estoppel, and the Owner Estoppel
given for such Lease will be of no further force and effect from and after the
date on which such Tenant Estoppel is delivered to the Company, but only to the
extent that such Tenant Estoppel confirms the pertinent statements made in such
Owner Estoppel.

                                       12
<Page>

        6.05.   To the extent requested by the Company in a written notice given
to Owner at least five (5) business days prior to the Closing (the "SERVICE
CONTRACT TERMINATION NOTICE"), Owner shall give written notices to the service
providers under the Service Contracts providing for such contracts to be
terminated effective as of the Closing or such later date that may be set forth
in the underlying Service Contract.

        6.06.   Prior to the Closing, Owner may enter into (or cause the
applicable SPE Entity to enter into) the easement more fully described in
EXHIBIT Q annexed hereto (the "TURNAROUND EASEMENT").

    Section 7.  SPECIAL RIGHT OF DELETION

        7.01.   (a) For purposes of this SECTION 7.01, the following terms shall
have the meanings ascribed to them below:

                        (i)     "DELETION EVENT" shall mean the occurrence of
any event, attributable solely to a Deletion Property, that would permit the
Company to terminate this Agreement in accordance with the provisions of this
Agreement.

                        (ii)    "DELETION PROPERTIES" shall mean those
Properties listed on EXHIBIT P annexed hereto.

                        (iii)   "DELETION PROPERTY" shall mean any of the
Deletion Properties.

                (b) If, prior to the Closing, a Deletion Event shall have
occurred and, as a result thereof, the Company shall have given a written notice
to Owner terminating this Agreement (the "DELETION TERMINATION NOTICE"), Owner
shall have the right, at its option, to cancel and nullify the Deletion
Termination Notice by giving written notice to the Company (within five (5)
business days' after Owner's receipt of the Deletion Termination Notice) that
Owner has deleted and eliminated the applicable Deletion Property from this
Agreement (the "DELETION NOTICE"). In the event that a Deletion Notice is given
by Owner, this Agreement shall, without further action of the parties, be deemed
to have been automatically and IPSO FACTO amended so as to eliminate each
Deletion Property so deleted by Owner, and the Contributed Equity Value and the
Cash Portion of the Sales Price shall be reduced by the value allocated by the
parties to the Deletion Property so deleted from this Agreement, as more fully
set forth in SCHEDULES 2.01(a) and 2.01(b), annexed hereto, and this Agreement
shall otherwise remain in full force and effect. Notwithstanding the foregoing,
Owner may not exercise its right of deletion under this SECTION 7.01(b) for more
than three (3) of the Deletion Properties.

                (c) If, prior to the Closing, a Deletion Event shall have
occurred due solely to the occurrence of a Property suffering a Material Loss
(as defined in SECTION 8.01(d)) and, as a result thereof, the Company shall have
given to Owner the Deletion Termination Notice, in addition to Owner's rights
under SECTION 7.01(b) above, Owner shall also have the right, at its option, in
lieu of providing the Company with a Deletion Notice (provided that the
insurance proceeds for restoration of the affected Deletion Property will be
made available to Owner), to cause the Company to accept title to such Property
without any abatement of any amount payable to Owner hereunder, in which event
Owner shall assign and turn over to the Company at the Closing, and the Company
shall be entitled to receive and keep, all amounts awarded or to be awarded as a
result of the taking of such Property or all insurance proceeds awarded or to be
awarded to Owner as a result of the damage or destruction to such Property, plus
the amount of the deductible under such insurance policy, each as the case may
be. Owner shall not settle or compromise any insurance claims or legal actions
relating to such Material Loss without the Company's prior consent, which
consent shall not be unreasonably withheld or delayed.

                                       13
<Page>

    Section 8.  DESTRUCTION, DAMAGE OR CONDEMNATION

        8.01.   (a) If, prior to the Closing Date, all or any portion of
the Properties is taken by eminent domain (or is the subject of a pending taking
which has not been consummated) and such taking results in a Material Loss (as
hereinafter defined), then, Owner shall notify the Company of such fact and the
Company shall have the option (which option shall be set forth in a notice from
the Company to Owner given not later than thirty (30) days after receipt of
Owner's notice):

                        (i)     to terminate this Agreement, and upon such
termination the Earnest Money shall be refunded to the Company, this Agreement
shall be null and void and the parties hereto shall be relieved of all further
obligations and liability to each other, except for the Surviving Obligations;
or

                        (ii)    to accept title to the Properties (other than
the portion so taken), without any abatement of any amount payable to Owner
hereunder, in which event Owner shall assign and turn over to the Company at the
Closing, and the Company shall be entitled to receive and keep, all amounts
awarded or to be awarded as the result of the taking of such Properties.

                (b) If, prior to the Closing Date, all or any portion of the
Properties is damaged or destroyed by fire or other casualty and such damage or
destruction results in a Material Loss, then Owner shall notify the Company of
such fact and the Company shall have the option (which option shall be set forth
in a written notice from the Company to Owner given not later than thirty (30)
days after receipt of Owner's notice):

                        (i)     to terminate this Agreement, and upon such
termination the Earnest Money shall be refunded to the Company, this Agreement
shall be null and void and the parties hereto shall be relieved of all further
obligations and liability to each other, except for the Surviving Obligations;
or

                        (ii)    to accept title to the Properties in their
existing condition without any abatement of any amount payable to Owner
hereunder, in which event Owner shall assign to the Company, at the Closing, all
of Owner's right, title and interest in and to the insurance proceeds awarded or
to be awarded to Owner as the result of such damage or destruction to such
Properties, and Owner shall not settle or compromise any insurance claims or
legal actions relating thereto without the Company's prior consent, which
consent shall not be unreasonably withheld or delayed.

                (c) If, prior to the Closing Date, all or any portion of the
Properties is damaged or destroyed by fire or other casualty or taken by eminent
domain and such damage or destruction or taking, as the case may be, does not
result in a Material Loss, then in the event of a fire or other casualty or a
taking such damage or destruction shall be repaired promptly by Owner, and in
the event the same is not repaired on or before the Closing Date, then Owner
shall assign to the Company any insurance proceeds or condemnation awards, as
the case may be, so that the Company may effect the necessary repairs after the
Closing, and Owner shall not settle or compromise any insurance claims or legal
actions relating thereto without the Company's prior consent, which consent
shall not be unreasonably withheld or delayed.

                (d) The term "MATERIAL LOSS" with respect to the Properties
shall mean damage or destruction to the Properties by fire or other casualty if
the cost of repair or replacement thereof exceeds $5,000,000 or by reason of a
taking by eminent domain if the diminution in value to the Properties exceeds
$5,000,000.

                                       14
<Page>

    Section 9.  COVENANTS OF OWNER

        9.01.   Owner covenants that between the date of this Agreement and the
Closing, subject to the limitations set forth in SECTION 1.03, Owner shall allow
the Company or the Company's representative's reasonable access to the
Properties, the Leases and other documents required to be delivered under this
Agreement upon reasonable prior notice at reasonable times during normal
business hours.

    Section 10. CONDITIONS PRECEDENT TO CLOSING

        10.01.  The Company's obligations hereunder are subject to the
satisfaction of the following conditions precedent on or before the Closing
Date:

                (a) Owner shall have delivered to or for the benefit of the
Company, on or before the Closing Date, all of the documents, other information
and payments, if any, required of Owner pursuant to SECTION 11 hereof.

                (b) All of Owner's representations and warranties made in this
Agreement shall be true and correct in all material respects as of the date
hereof and as of the Closing Date. Moreover, Owner shall have performed in all
material respects all of its covenants and other obligations hereunder.

                (c) Any material consent or notification required to be obtained
or given pursuant to the terms of any Lease or other material agreement
affecting the Properties in connection with the consummation of the transaction
contemplated by this Agreement shall have been obtained or given by Owner.

                (d) All of the Assumption Consents, IDA Approvals and IDA
Estoppels shall have been obtained.

                (e) This Agreement and the Operating Agreement, shall have been
duly authorized, executed and delivered by all of the parties hereto and thereto
(other than the Company).

                (f) Owner shall have satisfied or caused to be satisfied all
other conditions precedent set forth in this Agreement or any such unsatisfied
condition shall have been waived in writing by the Company.

                (g) The Title Company (hereinafter defined) shall be prepared to
issue standard form owner's title insurance policies for the Properties in the
name of the Company, subject to the Permitted Exceptions (as defined below).

                (h) Owner shall have delivered to or for the benefit of the
Company the requisite estoppel certificates provided for in SECTION 6.04.

                (i) All obligations of Owner and the SPE Entities under the
Brokerage Agreements shall have been paid, except for any commissions resulting
from the exercise following the Closing of renewal or expansion options by
tenants and except for any obligations under any new leases signed after the
date hereof pursuant to this Agreement;

                (j) All property management agreements affecting the Properties
shall have been terminated, effective as of the Closing, without liability for
the Company;

                                       15
<Page>

                (k) The mortgages presently securing the indebtedness of the
Company to Wells Fargo Bank shall have been assigned, without recourse, to any
lender designated by the Company (such assignment to be subject to any existing
limitations imposed by Wells Fargo Bank under the mortgages or other documents
governing such indebtedness); and

                (l) Each of the conditions contained in SECTIONS 10.01 (a)
THROUGH (k) are intended for the benefit of the Company and may be waived in
whole or in part, by the Company, but only by an instrument in writing signed by
the Company.

        10.02.  Owner's obligations hereunder are subject to, and expressly
contingent upon, the satisfaction of the following conditions precedent on or
before the Closing Date:

                (a) The Company shall have delivered to Owner all of the
documents and payments, if any, required of the Company pursuant to SECTION 12
hereof.

                (b) The Company shall have satisfied or caused to be satisfied
all other conditions precedent set forth in this Agreement or any such
unsatisfied condition shall have been waived by Owner.

                (c) All of the Company's representations and warranties made in
this Agreement shall be true and correct in all material respects as of the date
hereof and as of the Closing Date. Moreover, the Company shall have performed in
all material respects all of its respective covenants and other obligations
hereunder.

                (d) All of the Assumption Consents and IDA Approvals shall have
been obtained.

                (e) This Agreement and the Operating Agreement shall have been
duly authorized, executed and delivered by all of the parties hereto and thereto
(other than Owner).

                (f) That the Company will consummate, contemporaneously with the
Closing, a refinancing of the mortgage indebtedness encumbering the Wells Fargo
Properties (as defined in the Operating Agreement). Any prepayment penalties
imposed by the holder of such mortgage indebtedness in connection with such
refinancing, shall be paid by Owner.

                (g) Each of the conditions contained in SECTIONS 10.02(a)
THROUGH (e) are intended for the benefit of Owner and may be waived in whole or
in part, by Owner, but only by an instrument in writing signed by Owner.

        10.03.  If, prior to Closing, one or more of the Assumed Debt Holders
refuses to give an Assumption Consent to Owner, then Owner and the Company shall
amend this Agreement to provide for an alternative approach to enable the
Properties encumbered by the Assumed Debt to be transferred in a way that
complies with the Assumed Debt Holder's requirements, provided such requirements
are reasonable, do not increase any of the obligations and liabilities of Owner
and the Company and do not adversely affect any of the rights of the parties
hereto. Without limiting the foregoing, the Company will not be required to
agree to any change in the economic terms of the Assumed Debt or to any adverse
change in the nature, extent or application of the collateral now given as
security for the repayment of the Assumed Debt, except that the Company and the
New SPE Entities (as applicable) may be required to assume liability for the
performance of the non-recourse "carveouts" under the Assumed Debt. Subject to
SECTION 13.06(a), Owner shall pay all reasonable out-of-pocket expenses incurred
by the Company in

                                       16
<Page>

cooperating with Owner to effectuate such transfer in accordance with the
Assumed Debt Holder's requirements.

        10.04.  Owner's obligation to consummate the transaction contemplated by
this Agreement is further subject to and contingent upon the approval thereof by
the Board of Directors of Keystone Property Trust, the general partner of Owner
(the "BOARD APPROVAL"). Upon the occurrence of Board Approval, written notice
thereof (the "BOARD APPROVAL NOTICE") may be given by Owner to the Company on or
before July 9, 2002 and between July 22, 2002 and July 26, 2002. If the Board
Approval Notice is not given by Owner to the Company by July 26, 2002 (time
being of the essence with respect to such date), this Agreement shall terminate
without further act or instrument, in which event the Earnest Money and all
reasonable out-of-pocket expenses incurred by the Company for third party
diligence reports with respect to the Properties shall be refunded to the
Company, this Agreement shall be null and void and the parties hereto shall be
relieved of all further obligations and liability to each other, except for
Surviving Obligations.

    Section 11. OWNER'S CLOSING OBLIGATIONS

        11.01.  At the Closing, Owner shall deliver the following to the
Company:

                (a) original copies of all Leases, IDA Leases, Pilot Agreements,
ground leases, reciprocal easement agreements and other similar documents
relating to the Properties, to the extent in Owner's possession or subject to
its control;

                (b) a schedule of all cash security and similar deposits,
including any interest thereon, held by or on behalf of Owner on the Closing
Date under the Leases;

                (c) a schedule updating the Rent Rolls and setting forth all
arrearages in rents and Additional Rents and all prepayments of rents and
Additional Rents;

                (d) all Service Contracts (other than those included in the
Service Contract Termination Notice) which are in effect on the Closing Date and
which are assignable by Owner;

                (e) an assignment to the Company of all of the interest of Owner
in those Service Contracts, certificates, permits and other documents to be
delivered to the Company at the Closing which are then in effect and are
assignable by Owner;

                (f) to the extent they are then in Owner's possession or subject
to its control and not posted at the Properties or issued directly to tenants of
the Properties, certificates, licenses, permits, authorizations and approvals
issued for or with respect to the Properties by governmental or
quasi-governmental authorities having jurisdiction thereover;

                (g) a certification of non-foreign status, in form required by
the Code Withholding Section, signed under penalty of perjury. Owner understands
that such certification will be retained by the Company and will be made
available to the Internal Revenue Service on request;

                (h) an original letter executed by Owner or by its agent,
advising the tenants of the transfer of the Contributed Properties and the Sale
Properties to the Company and directing that rents and other payments thereafter
be sent to the Company or as the Company may direct;

                (i) corporate resolutions, certificates of good standing,
incumbency certificates and other evidence of authority with respect to Owner;

                                       17
<Page>

                (j) possession of the Properties and in the condition required
by this Agreement, subject to the Leases, and keys therefor;

                (k) the IDA Approvals and the IDA Estoppels;

                (l) the Assumption Consents;

                (m) executed and acknowledged deeds conveying to the Company and
the New SPE Entities, as applicable, fee simple title to the Contributed
Properties and the Sale Properties (except for any of such Properties in which
fee simple title is vested in a governmental or quasi-governmental authority),
subject to the Permitted Exceptions;

                (n) executed and acknowledged assignments and assumptions of
ground leases (collectively, the "ASSIGNMENTS OF GROUND LEASES"), assigning and
transferring to the Company and the New SPE Entities, as applicable, all right,
title and interest of Owner in and to, and all post-Closing obligations of the
lessee under, the IDA Leases and all other ground leases affecting the
Contributed Properties and the Sale Properties;

                (o) executed and acknowledged assignments and assumptions of
leases (collectively, the "ASSIGNMENTS OF LEASES"), assigning and transferring
to the Company and the New SPE Entities, as applicable, all right, title and
interest of Owner in and to, and all post-Closing obligations of the lessor
under, all Leases affecting the Contributed Properties and the Sale Properties;

                (p) executed bills of sale transferring to the Company and the
New SPE Entities, as applicable, all personal property owned by Owner and
located at or attached to the Contributed Properties and the Sale Properties;

                (q) transfer tax returns and/or certificates (including the New
York State Real Property Transfer Tax Return and Credit Line Mortgage
Certificate ("TP-584") and the New York State Real Property Transfer Report
("RP-5217"));

                (r) executed assignments and assumptions of the Pilot Agreements
(collectively, the "ASSIGNMENTS OF PILOT AGREEMENTS"), assigning to the Company
and the New SPE Entities, as applicable, all right, title and interest of Owner
in and to, and all post-Closing obligations of Owner and the SPE Entities, as
applicable, under the Pilot Agreements; and

                (s) to the extent required by applicable laws and regulations to
record any deed to any of the Properties, a certificate of regularity or
occupancy from the appropriate governmental authority; and

                (t) any other documents required by this Agreement to be
delivered by Owner.

    Section 12. THE COMPANY'S CLOSING OBLIGATIONS

        12.01.  At the Closing, the Company (or the appropriate New SPE Entity)
shall deliver the following to Owner or the appropriate party (if not Owner):

                (a) by wire transfer(s) of immediately available federal funds
to Owner in payment of the Cash Portion of the Sales Price (plus or minus net
adjustments and prorations pursuant to SECTION 13);

                                       18
<Page>

                (b) an executed assumption by the Company of all of the
interests of Owner in those Service Contracts, certificates, permits and other
documents to be delivered to the Company at the Closing which are then in effect
and are assignable by Owner;

                (c) executed instruments assuming the Assumed Debt;

                (d) executed and acknowledged Assignments of Ground Leases,
Assignments of Leases and the Assignments of Pilot Agreements;

                (e) all documents and other instruments and certificates
(executed and acknowledged, where appropriate) required of the Company to comply
with all the requirements of the Assumed Debt Holders in order to obtain the
Assumption Consents; and

                (f) any other documents required by this Agreement to be
delivered by the Company (executed and acknowledged, where appropriate).

    Section 13. APPORTIONMENTS

        13.01.  The following apportionments shall be made between the parties
at the Closing as of 12:00 midnight on the day prior to the Closing Date:

                (a) rent payments (including prepaid rents) and Additional Rents
(as defined in SECTION 13.03) actually received under the Leases;

                (b) to the extent not paid directly by tenants under the Leases,
water charges, sewer rents other utility charges and vault charges, if any, on
the basis of the fiscal period for which assessed, except that if there is a
water meter at the Properties, apportionment at the Closing shall be based on
the last available reading, subject to adjustment after the Closing when the
next reading is available;

                (c) value of fuel stored at the Properties at the price then
charged by Owner's supplier, including any taxes;

                (d) charges under transferable Service Contracts and other
transferable agreements pertaining solely to the Properties or permitted
renewals or replacements thereof;

                (e) permitted administrative charges, if any, on tenants'
security deposits;

                (f) amounts payable by the Company and the SPE Entities, as
applicable, under the Pilot Agreements;

                (g) rent under all ground leases affecting the Properties;

                (h) interest under the Assumed Debt;

                (i) to the extent not paid directly by tenants to taxing
authorities pursuant to the Leases, real estate taxes and personal property
taxes for the current fiscal year;

                (j) outstanding leasing commissions and tenant improvement
obligations of the landlord under any new or renewal leases entered into after
the date hereof pursuant to SECTION 6.01 (such apportionment to be made based on
the fixed term of such new or renewal lease); and

                                       19
<Page>

                (k) salary and benefits for any of the Employees retained by the
Company.

        13.02.  The adjustment of real estate and personal property taxes shall
be made on the basis of presently available evidence of such taxes, subject to
adjustment by payment from Owner to the Company, or the Company to Owner,
whichever is applicable, after the Closing due to any change in assessment,
applicable rate or other reason. Notwithstanding the foregoing, all special
assessments, if any, that are a lien as of the Closing shall be paid by Owner.

        13.03.  The following adjustments to the Cash Portion of the Sales Price
shall be made between the parties at the Closing:

                (a) The Company shall be credited and Owner charged with
security deposits (together with any interest accrued thereon) or advance
rentals made by tenants under the Leases and any additional leases entered into
by Owner pursuant to SECTION 6.01;

                (b) Owner shall be credited and the Company charged with
transferable deposits under any Service Contracts assigned to the Company at the
Closing;

                (c) Owner shall be credited and the Company charged with escrow
deposits maintained under the Assumed Debt; and

                (d) The Company shall be credited and Owner charged with all
leasing commissions and tenant improvement obligations set forth in EXHIBITS K
AND L attached hereto, to the extent same applies to Leases in effect as of the
Closing (but not including any commissions that may result from the exercise
after the Closing of renewal or expansion options by tenants).

        13.04.  If any tenant is in arrears in the payment of rent or Additional
Rent on the Closing Date, rents received from such tenant after the Closing
shall be applied in the following order of priority: (a) FIRST to the month in
which the Closing occurred; (b) THEN to any month or months following the month
in which the Closing occurred; and (c) THEN to any month or months preceding the
month in which the Closing occurred. If rents or Additional Rents or any portion
thereof received by Owner or the Company after the Closing are payable to the
other party by reason of this allocation, the appropriate sum, less a
proportionate share of any reasonable attorneys' fees, out-of-pocket costs and
expenses of collection thereof, shall be promptly paid to the other party, which
obligation shall survive the Closing. Owner shall have the right to collect any
such arrearages following the Closing other than by summary proceedings (such
right shall survive the Closing).

        13.05.  If any tenant is required to pay percentage rent, escalation
charges for real estate taxes, common area maintenance charges, operating
expenses, cost-of-living adjustments or other charges of a similar nature
("ADDITIONAL RENT"), and any Additional Rent is collected by the Company after
the Closing which accrued prior to the Closing, then the Company shall promptly
pay Owner's proportionate share thereof to Owner, less any reasonable attorneys'
fees, and any other reasonable out-of-pocket costs and expenses of collection
thereof, which obligation shall survive the Closing.

        13.06.  The following shall apply to closing costs:

                (a) At the Closing, the Company shall pay (i) up to $1,250,000
of the costs incurred in this transaction relating to the obligation to obtain
the Assumption Consents, IDA Approvals and IDA Estoppels, (ii) 50% of the state
and local transfer taxes required to be paid in Pennsylvania, (iii) all costs on
any document recorded pursuant to this Agreement or the Operating Agreement,
(iv) the cost

                                       20
<Page>

of title insurance premiums, including any extended coverage and endorsements,
incurred in connection with the issuance of the Title Policy, and (v) the cost
of the survey.

                (b) At the Closing, Owner shall pay (i) all costs above
$1,250,000 incurred in this transaction relating to the obligation to obtain the
Assumption Consents, IDA Approvals and IDA Estoppels, (ii) 50% of the state and
local transfer taxes required to be paid in Pennsylvania, (iii) 100% of the
state and local transfer taxes, required to be paid in New York and Ohio, and
(iv) all recording fees on any document recorded pursuant to this Agreement to
discharge liens and encumbrances which are not Permitted Exceptions.

                (c) Except as expressly set forth herein, each party shall pay
its own attorney's fees and all of its other costs and expenses.

        13.07.  Owner and the Company acknowledge that there are presently real
estate tax review proceedings pending with respect to certain of the Properties
(collectively, the "CERTIORARI PROCEEDINGS"). Owner and the Company agree that
the Certiorari Proceedings shall continue to be handled by Deloitte & Touche
(the "TAX CERTIORARI ADVOCATE"). All reductions in real estate taxes resulting
from the Certiorari Proceedings and attributable to any tax period prior to the
Closing Date shall belong and be paid to Owner, less the fees and disbursements
of the Tax Certiorari Advocate and less any portion of such reduction required
to be paid to tenants pursuant to the Leases. Owner shall indemnify and hold the
Company harmless from any claims asserted by tenants under the Leases that any
amounts paid to Owner by the Company should have instead been paid to such
tenants. Owner shall not settle or compromise any Certiorari Proceeding relating
to a tax year in which the Closing occurs and any subsequent tax years without
the Company's prior consent, which consent shall not be unreasonably withheld or
delayed. The provisions of this SECTION 13.07 shall survive the Closing.

    Section 14. OBJECTIONS TO TITLE; FAILURE OF OWNER OR THE COMPANY TO PERFORM

        14.01.  (a)     Owner shall cause Fidelity National Title Insurance
Company (the "TITLE COMPANY"), acting through its national office in
Philadelphia, Pennsylvania (the "PHILLY OFFICE"), to issue to the Company,
within fifteen (15) days from the date hereof, a title insurance commitment for
each of the Properties (collectively, the "TITLE COMMITMENTS"). The Philly
Office and Sutton Land Services, an abstract company engaged by the Company,
shall work together in handling all subsequent title matters relating to the
issuance of the Title Policies (hereinafter defined), the recordation of
conveyance documents and the filing of transfer tax returns. The receipt and
distribution of funds at the Closing shall be handled by the Philly Office. The
title insurance policies to be issued at the Closing by the Title Company,
directly or through its agent designated by the Company, pursuant to the Title
Commitments (collectively, the "TITLE POLICIES") shall be standard forms of
owner's policies, in the collective amount of $178,300,000. Owner shall cause
the Title Policies to be issued to the Company, subject only to the exceptions
set forth in EXHIBIT N annexed hereto (the "PERMITTED EXCEPTIONS") and free and
clear of all standard or general exceptions contained in the Title Commitments
which Escowee is permitted by applicable law to remove or modify upon delivery
of the Existing Surveys and standard title affidavits from Owner.

                (b)     Owner shall promptly deliver to the Company a copy of
any existing survey of the Properties within Owner's possession or subject to
its control (the "EXISTING SURVEYS").

                (c)     Prior to the expiration of the Due Diligence Period, the
Company shall give a written notification to Owner (the "DEFECTS NOTICE") of any
claim, lien, encumbrance or exception affecting title to the Properties (other
than the Permitted Exceptions) and which the Company is not willing to waive
(each, a "DEFECT"). Owner shall have the right, but not the obligation, to cure
any Defect

                                       21
<Page>

within twenty (20) days after its receipt of the Defects Notice, or in the case
of any Defect which cannot with due diligence be cured within such 20-day
period, such later date by which such Defect can reasonably be cured, provided
that Owner commences to cure such Defect within such 20-day period and
thereafter continues diligently and in good faith to cure the Defect. The
Closing shall be extended, if necessary, in order to permit the cure described
above, but in no event shall the date of the Closing be extended for more than
thirty (30) days. In the event that Owner elects not to cure any such Defect,
Owner shall notify the Company of such election within five (5) business days
after its receipt of the Defects Notice. Owner shall have no obligation to cure
any Defect created solely by any acts or omissions of the Company, and Owner's
failure to cure any such Defect shall not relieve the Company from its
obligation to close under this Agreement. If Owner elects not to cure any Defect
(or fails to notify the Company of Owner's election not to cure any Defect) as
set forth above or, if by the expiration of the cure period provided for above,
Owner has failed to cure all Defects (other than any Defects created solely by
any acts or omissions of the Company), the Company may, at its option, either
(i) proceed to close subject to any such Defects, with no offset against, or
reduction in, any amount payable to Owner hereunder or (ii) terminate this
Agreement by written notice given to Owner within five (5) business days after
the expiration of the cure period or Owner's notice of election not to cure any
Defect, as the case may be. In the event this Agreement is so terminated by the
Company, the Earnest Money (if paid by the Company to Escrowee) and all interest
earned thereon shall be delivered to the Company and the parties shall be
released from all further obligations and liabilities hereunder, except for the
Surviving Obligations. Notwithstanding anything to the contrary contained in
this SECTION 14.01, in the event that any Defect(s) is a mechanic's or
materialmen's lien (not including any mechanic's or materialmen's lien created
by a tenant of the Properties which such tenant is obligated to remove pursuant
to its lease or sublease, provided that such tenant is not otherwise in default
of a monetary obligation under its lease or sublease) securing the payment, in
the aggregate, of a readily ascertainable sum of money of up to $5,000,000 or a
monetary encumbrance against the Property created by Owner, Owner shall satisfy
such Defect(s) of record or, as an alternative to causing such Defect(s) to be
satisfied of record and provided that Escrowee agrees to omit such Defect(s)
from the Title Policies: (i) bond or cause to be bonded such Defect(s); (ii)
deliver or cause to be delivered to Escrowee, on the date of the Closing,
instruments in recordable form and sufficient to satisfy such Defect(s) of
record, together with the appropriate recording or filing costs; or (iii)
deposit or cause to be deposited with Escrowee sufficient monies, acceptable to
and reasonably requested by Escrowee, to assure the obtaining and recording of a
satisfaction of the Defect(s).

        14.02.  If, prior to the Closing, the Company shall materially default
in the performance of any of its obligations under this Agreement, or shall
materially breach any of its representations or warranties contained in this
Agreement, and such default or breach shall remain uncured for ten (10) days
after the Company receives written notice thereof from Owner, then Owner shall
have the right, as its sole remedy, to terminate this Agreement and receive the
Earnest Money and all interest earned thereon from Escrowee as liquidated
damages, it being understood that Owner's damages in such event would be
substantial, but extremely difficult, if not impossible, to ascertain. Upon such
termination, neither Owner nor the Company shall have any rights or liabilities
hereunder, except for the Surviving Obligations.

        14.03.  If Owner shall fail to close the transactions contemplated by
this Agreement because of a material default in the performance of any of
Owner's obligations, or a material breach of any of its representations or
warranties contained in this Agreement, the Company shall have, as its sole and
exclusive remedy, the right to sue for specific performance of this Agreement.

    Section 15. BROKER

        15.01.  Owner and the Company mutually represent and warrant to each
other that neither Owner nor the Company knows of, or has dealt with, any
broker, finder, salesperson or similar

                                       22
<Page>

agent who has claimed or may have the right to claim a commission in connection
with this transaction, except for Bear Stearns & Co., Inc. ("BEAR STEARNS") and
Pioneer Management Services Company, LLC ("PIONEER"). At the Closing, Owner
shall pay a commission to Bear Stearns pursuant to a separate agreement between
Owner and Bear Stearns. At the Closing, the Company shall pay a commission to
Pioneer pursuant to a separate agreement between the Company and Pioneer. Owner
and the Company shall indemnify and defend each other against any costs, claims
or expenses, including reasonable attorneys' fees, arising out of the breach on
their respective parts of the representations and warranties or agreements
contained in this section. The representations and obligations under this
paragraph shall survive the Closing or, if the Closing does not occur, the
termination of this Agreement.

    Section 16. NOTICES

        16.01.  All notices, requests, demands and other communications
hereunder shall be in writing and shall be delivered by hand (with receipt for
delivery), transmitted by facsimile transmission (if also delivered by any other
method of delivery provided for in this SECTION 16.01), sent prepaid by Federal
Express for next business day delivery, with receipt for delivery (or a
comparable overnight delivery service), at the addresses and with such copies as
designated below:

        If to Owner:

        Keystone Operating Partnership, L.P.
        200 Four Falls Corporate Center, Suite 208
        West Conshohocken, Pennsylvania 19428
        Attn: Saul A. Behar, Esq.
        Fax:  (484) 530-0131

        with a copy to

        Clifford Chance Rogers & Wells LLP
        200 Park Avenue
        New York, New York 10166
        Attn: Robert King, Jr., Esq.
              Jeffrey H. Weitzman, Esq.
        Fax:  (212) 878-8375

        If to the Company:

        Nocha LLC
        c/o JFR Global Investments
        1302 46th Street
        Brooklyn, New York 11219
        Attn: Joseph Friedland
        Fax:  (718) 436-4898

        with a copy to:

        Frenkel, Hershkowitz & Shafran LLP
        16 East 34th Street, 16th Floor
        New York, New York 10016
        Attn: Joseph M. Hershkowitz, Esq.
        Fax:  (212) 889-5072

                                       23
<Page>

        Any notice, request, demand or other communication delivered or sent in
the manner aforesaid shall be deemed given or made (as the case may be) when
actually delivered to the intended recipient or to such other address as the
intended recipient may have specified in a notice to the other party. Any party
hereto may change its address or designate different or other persons or
entities to receive copies by notifying the other party in a manner described in
this SECTION 16. Notices hereunder from either party may be given by their
attorneys.

    Section 17. LIMITATIONS ON SURVIVAL OF REPRESENTATIONS, WARRANTIES,
                COVENANTS AND OTHER OBLIGATIONS

        17.01.  Except as otherwise provided in this Agreement, no
representations, warranties, covenants or other obligations of Owner set forth
in this Agreement shall survive the Closing, and, for the referenced items not
surviving the Closing, no action based thereon shall be commenced after the
Closing. The representations and warranties of Owner and the Company set forth
in SECTION 4 shall survive for a period of one year after the Closing (the
"LIMITATION PERIOD").

    Section 18. MISCELLANEOUS PROVISIONS

        18.01.  The Company shall not assign this Agreement or its rights
hereunder without the prior written consent of Owner, except that the Company
shall have the right to assign this Agreement to an Affiliate (as hereinafter
defined) of the Company. "AFFILIATE" means any person or business entity that
controls (as hereinafter defined), is controlled by or is under common control
with, another person or business entity, and "CONTROL" means the power, directly
or indirectly, to direct the actions, operation or management of another person
or business entity by contract, the ownership of voting rights or otherwise. No
permitted assignment of the Company's rights under this Agreement shall be
effective against Owner unless and until an executed counterpart of the
instrument of assignment and assumption of the Company's obligations hereunder
shall have been delivered to Owner and Owner shall have been furnished with the
name and address of the assignee. The term "THE COMPANY" shall be deemed to
include the assignee under any such effective assignment and assumption.

        18.02.  This Agreement embodies and constitutes the entire understanding
between the parties with respect to the contribution and sale of the Contributed
Properties and the Sale Properties to the Company, and all prior agreements,
understandings, representations and statements, oral or written, are merged into
this Agreement.

        18.03.  Neither this Agreement nor any provision hereof may be waived,
modified, amended, discharged or terminated except by an instrument signed by
both parties hereto, and then only to the extent set forth in such instrument.

        18.04.  This Agreement shall be governed by, and construed in accordance
with, the law of the State of New York without regard to its principles of
conflicts of law.

        18.05.  The captions in this Agreement are inserted for convenience of
reference only and in no way define, describe or limit the scope or intent of
this Agreement or any of the provisions hereof.

        18.06.  This Agreement shall be binding upon and shall inure to the
benefit of the parties hereto and their respective successors and permitted
assigns.

        18.07.  As used in this Agreement, the masculine shall include the
feminine and neuter, the singular shall include the plural and the plural shall
include the singular, as the context may require.

                                       24
<Page>

        18.08.  If the provisions of any schedule or rider to this Agreement are
inconsistent with the provisions of this Agreement, the provisions of such
schedule or rider shall prevail.

        18.09.  This Agreement may be executed in one or more counterparts, such
of which shall constitute an original and all of which, when taken together
shall constitute a single instrument.

        18.10.  This Agreement shall not be recorded.

        18.11.  This Agreement is for the sole benefit of the parties hereto and
their respective successors and permitted assigns, and no other person or entity
shall be entitled to rely upon or receive any benefit from this Agreement or any
term hereof.

        18.12.  No general or limited partner of Owner, no officer, director,
stockholder or partner of a partner of Owner, no disclosed or undisclosed
principal of Owner, and no person or entity in any way affiliated with Owner
shall have any personal liability with respect to this Agreement, any instrument
delivered by Owner at the Closing, or the transaction contemplated hereby, nor
shall the property of any such person or entity be subject to attachment, levy,
execution or other judicial process.

        18.13.  The submission of this Agreement for examination does not
constitute an offer by or to either party. This Agreement shall be effective and
binding only after due execution and delivery by the parties hereto.

        18.14.  No member of the Company, no officer, director, stockholder or
partner of a member of the Company, no disclosed or undisclosed principal of the
Company, and no person or entity in any way affiliated with the Company shall
have any personal liability with respect to this Agreement, any instrument
delivered by the Company at the Closing, or the transaction contemplated hereby,
nor shall the property of any such person or entity be subject to attachment,
levy, execution or other judicial process.

    Section 19. PRESS RELEASE

        19.01.  The parties agree that, prior to the Closing, no party shall
issue any press release or otherwise publicize or disclose the terms of this
Agreement or the terms of acquisition or disposition of any of the Properties or
the transactions contemplated hereby (other than to agents, advisors,
prospective lenders or investors, mortgage brokers and others who have a need to
know, actually or prospectively, and who agree to keep such information
confidential as provided herein) without the prior written consent of the other
party except such disclosure as may be required by or pursuant to law or the
rules and regulations of the New York Stock Exchange or the Securities and
Exchange Commission.

        19.02.  The provisions of this SECTION 19 shall survive the Closing or
the sooner termination of this Agreement.

    Section 20. DEFINITIONS

    For the purposes of this Agreement, the following terms shall have the
respective meanings set forth below:

    "IDA AGENCIES" shall mean the City of Syracuse Industrial Development
Agency and the County of Monroe Industrial Development Agency.

                                       25
<Page>

    "IDA APPROVALS" shall mean written notices from each respective IDA Agency
approving the transfer to the Company (or its permitted designee) of an IDA
Lease and any related Pilot Agreement.

    "IDA ESTOPPELS" shall mean written notices from each respective IDA Agency
confirming (i) that each IDA Lease is in full force and effect, the date to
which rent thereunder has been paid and, to the knowledge of the IDA Agency,
that no default exists thereunder and (ii) that each Pilot Agreement (to the
extent in existence) is in full force and effect, the date to which payments
thereunder have been made and, to the knowledge of the IDA Agency, that no
default exists thereunder.

    "IDA LEASES" shall mean those certain lease agreements between Owner (or a
SPE Entity) and an IDA Agency and more fully described in EXHIBIT "R" annexed
hereto.

    "PILOT AGREEMENTS" shall mean those certain agreements providing for
"payment in lieu of taxes" between Owner (or a SPE Entity) and an IDA Agency and
more fully described in EXHIBIT "S" annexed hereto.


         [The remainder of this page has been intentionally left blank.]

                                       26
<Page>

        IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the date first above written.

                              OWNER:

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


                                 By:  KEYSTONE PROPERTY TRUST,
                                      a Maryland real estate investment trust,
                                      General Partner


                                      By: /s/ Robert F. Savage, Jr.
                                         ----------------------------
                                      Name: Robert F. Savage, Jr.
                                      Title: Executive Vice President


                              COMPANY:


                              NOCHA LLC,
                              a New York limited liability company


                                      By: /s/ Joseph Friedland
                                         ---------------------------------
                                          Name:  Joseph Friedland
                                          Title: Vice President

        The undersigned joins in the execution of this Agreement solely to
confirm its acceptance of its obligations pursuant to SECTION 2.02 hereof:

ESCROWEE:


FIDELITY NATIONAL TITLE INSURANCE COMPANY OF NEW YORK


By: /s/ Robert L. Simon
    ------------------------------
   Name:  Robert L. Simon
   Title: Senior Vice President

                                       27