<PAGE>



                  AGREEMENT FOR PURCHASE AND SALE OF SECURITIES


                                 BY AND BETWEEN


                             KEYSTONE PROPERTY TRUST
                                    ("BUYER")


                                       AND


                CRESCENT REAL ESTATE EQUITIES LIMITED PARTNERSHIP
                                   ("SELLER")



                           DATED AS OF APRIL 16, 2001


<PAGE>

                                                                    EXHIBIT 10.1

                            STOCK PURCHASE AGREEMENT


      STOCK PURCHASE AGREEMENT, dated as of April 16, 2001 (the "Agreement") by
and between Crescent Real Estate Equities Limited Partnership, a Delaware
limited partnership ("SELLER") and Keystone Property Trust, a Maryland real
estate investment trust ("BUYER").

      WHEREAS, Seller desires to sell and transfer to Buyer the securities
described on Exhibit A hereto (the "SECURITIES") and Buyer wishes to acquire the
Securities on the terms set forth in this Agreement.

      THEREFORE, the parties hereto agree as follows:

      1. SALE AND PURCHASE OF THE SECURITIES. Seller hereby agrees to assign,
sell, convey and transfer to Buyer on the dates and in the amounts indicated in
EXHIBIT B hereto (each a "CLOSING DATE") all right, title and interest of Seller
in and to the Securities and Buyer, in reliance on the representations and
warranties set forth herein, agrees to pay Seller the Purchase Price (as defined
herein) in respect of such sale. The certificates representing certain of the
common shares of beneficial interest of Buyer ("COMMON SHARES"), as listed on
EXHIBIT A hereto, shall be in genuine and unaltered form, duly endorsed in blank
by Seller, or accompanied by a stock power duly executed by Seller, and
delivered to Buyer on each applicable Closing Date. On the initial Closing Date
as indicated on EXHIBIT B, each of Buyer and Seller shall instruct DTC to record
the transfer to the Buyer of any uncertificated common shares owned by Seller
being purchased on such Closing Date. The Securities shall be free and clear of
all liens, pledges, claims, security interests, encumbrances, charges,
restrictions or limitations of any kind, whether arising by agreement, operation
of law or otherwise (collectively, "LIENS"). The aggregate purchase price shall
be $30,126,155.50 (the "PURCHASE PRICE"), which represents a per share or unit
price of $12.25, subject to a purchase price adjustment of $0.31 per share/unit
($762,376.18 in the aggregate). Buyer shall pay, in accordance with EXHIBIT B,
the applicable portion of the Purchase Price, as adjusted, to the Seller in
immediately available funds by wire transfer on the applicable Closing Date to
an account designated by the Seller in writing at least two business days prior
to such Closing Date.

      2. REPRESENTATIONS AND WARRANTIES OF SELLER. Seller hereby represents and
warrants to Buyer that each of the following statements is true and correct as
of the date hereof and will be true and correct as of each Closing Date as if
made on such date.

      (a) Seller is duly organized, validly existing and in good standing in the
state of its organization, with full partnership power and authority to carry on
its business as it is now operated and carried on by it.

      (b) Seller has good and marketable title to the Securities, and Seller
will convey to Buyer good, valid and marketable title to the Securities free and
clear of all Liens.

      (c) Seller has all requisite partnership power and authority to execute
and deliver this Agreement and to perform its obligations hereunder and to
consummate the transactions contemplated hereby. This Agreement has been duly
authorized, executed and delivered by Seller and constitutes a valid and binding
agreement of Seller enforceable against Seller in accordance with its terms.

      (d) The execution, delivery and performance of this Agreement by Seller
and the consummation of the transactions contemplated hereby do not and will not
violate or be in conflict with, or constitute a breach of or default (or an
event which, with notice or lapse of time or both, would constitute a default)
under the terms of any law, regulation, order, judgment, instrument, contract,
license or other agreement to which Seller is a party or by which Seller or its
assets are bound or which would

<PAGE>

prevent the consummation of this transaction, and no consent or approval of any
third party or any government, state, province, county or other political
subdivision thereof, or any entity exercising executive, legislative, judicial,
regulatory or administrative function of, or pertaining to, governing
(collectively, "Governmental Authority") is necessary in order to permit Seller
to execute and deliver this Agreement and perform the transactions contemplated
hereby.

      (e) The Seller has not sold, transferred, pledged or otherwise disposed
of, or converted or exchanged, or granted any option or other right with respect
to, any of the Securities.

      (f) Seller has not employed any broker or finder or incurred any liability
for any brokerage fees or commissions in connection with the transactions
contemplated by this Agreement.

      (g) There is no suit, claim, action, proceeding or investigation pending
or, to the Seller's knowledge, threatened against the Seller or its affiliates
or any of their predecessors with respect to the Securities at law or in equity
or before any Governmental Authority or before any arbitrator of any kind and,
to the Seller's knowledge, there is no reasonable basis for any such suit,
claim, action, proceeding or investigation. The Seller has not been a party to
any such suit, claim, action, proceeding or investigation during the past two
years relating to the Securities, nor has any such suit, claim, action,
proceeding or investigation been threatened in writing by or against the Seller.

      (h) Seller acknowledges that neither the Buyer nor any of its agents or
affiliates solicited the sale of the Securities by Seller and that the
transactions contemplated hereby qualifies as an "unsolicited purchase" under
Rule 102 of Regulation M promulgated under the rules and regulations of the
Securities Act of 1933, as amended.

      3. REPRESENTATIONS AND WARRANTIES OF BUYER. Buyer hereby represents and
warrants to Seller that each of the following statements is true and correct as
of the date hereof and will be true and correct as of each Closing Date as if
made on such date.

      (a) Buyer is duly organized, validly existing and in good standing in the
state of its incorporation, with full trust power and authority to carry on its
business as it is now operated and carried on by it. Buyer has all requisite
trust power and authority to execute and deliver this Agreement and to perform
its obligations hereunder and to consummate the transactions contemplated
hereby. This Agreement has been duly authorized, executed and delivered by Buyer
and constitutes a valid and binding agreement of Buyer enforceable against Buyer
in accordance with its terms.

      (b) The execution, delivery and performance of this Agreement by Seller
and the consummation of the transactions contemplated hereby do not and will not
violate or be in conflict with, or constitute a breach of or default (or an
event which, with notice or lapse of time or both, would constitute a default)
under the terms of any law, regulation, order, judgment, instrument, contract,
license or other agreement to which Buyer is a party or by which Buyer or its
assets are bound or which would prevent the consummation of this transaction,
and no consent or approval of any Governmental Authority is necessary in order
to permit Buyer to execute and deliver this Agreement and perform the
transactions contemplated hereby.

      (c) Buyer has not employed any broker or finder or incurred any liability
for any brokerage fees or commissions in connection with the transactions
contemplated by this Agreement.

      4. COVENANTS.

<PAGE>

      (a) From the date hereof until the last Closing Date, Seller will not, and
will direct its employees, agents and other representatives (including, without
limitation, any financial advisor, attorney or accountant retained by Seller)
not to, directly or indirectly, solicit, encourage, or participate in any way in
discussions or negotiations with, or provide any information, data or assistance
to, any third party (other than Buyer and its affiliates) concerning any
acquisition of, or other transaction involving, the Securities. Seller will
promptly communicate to Buyer in writing the terms of any proposal or contact it
may receive in respect of any such transaction.

      (b) Each party to this Agreement shall execute and deliver, or cause to be
executed and delivered, all such instruments and shall take all such actions as
the other party may reasonably request in order to effect the intent and
purposes of and to carry out the terms of this Agreement.

      (c) Seller shall give Buyer and its authorized representatives, at all
reasonable times during regular business hours and on reasonable advance notice,
access to all information reasonably available to it which is necessary to Buyer
to enable Buyer to evaluate the merits and risks of purchasing the Securities.

      (d) The Seller shall not sell, transfer, pledge or otherwise dispose of,
or convert or exchange, or grant any option or other right with respect to, any
of the Securities.

      (e) Seller shall not exercise its conversion rights with respect to any of
its common units of limited partnership in Keystone Operating Partnership, L.P.
(the "OPERATING PARTNERSHIP").

      5. SURVIVAL OF REPRESENTATIONS AND WARRANTIES, COVENANTS AND AGREEMENTS.
All representations, warranties, covenants and agreements contained or made in,
or in connection with, this Agreement shall survive each Closing Date,
notwithstanding any investigation conducted with respect thereto or any
knowledge acquired as to the accuracy or inaccuracy of any such representation
or warranty or any breach or non-performance of any such covenant or agreement.

      6. INDEMNIFICATION.

      (a) Seller agrees to defend, indemnify and hold harmless Buyer, and its
trustees, officers, employees, agents and any of their successors and assigns,
from and against any and all losses, damages, claims, suits, proceedings,
liabilities, costs and expenses (including settlement costs, interest,
penalties, reasonable attorney's fees and any reasonable legal or other expenses
for investigation or defense of any actions or threatened actions)
(collectively, "LOSSES" or "CLAIMS," as the context requires) which may be
imposed, sustained, incurred or suffered or asserted as a result of, relating to
or arising out of (i) the breach of any representation or warranty of Seller
contained in this Agreement; (ii) any failure by Seller to perform any covenant,
agreement or obligation of Seller contained in this Agreement; and (iii)
Seller's ownership of the Securities prior to the last Closing Date, including
liabilities for taxes, charges, fees and periodic deposits (including interest
and penalties) determined to have been due to any Governmental Authority during
the period that Seller owned or held the Securities.

      (b) Buyer agrees to defend, indemnify and hold harmless Seller and its
partners, officers, directors, employees, agents and any of their successors and
assigns from and against any and all Losses or Claims which may be imposed,
sustained, incurred or suffered or asserted as a result of, relating to or
arising out of (i) the breach of any representation or warranty of Buyer
contained in this Agreement; and (ii) any failure by Buyer to perform any
covenant, agreement or obligation of Buyer contained in this Agreement.

<PAGE>

      7. CONFIDENTIALITY. All information furnished in writing by one party to
this Agreement to another party to this Agreement in connection with this
Agreement and the transactions contemplated hereby shall be kept confidential by
the receiving party and shall be used by the receiving party only in connection
with this Agreement and the transactions contemplated hereby, except to the
extent that such information (i) is information which the receiving party can
demonstrate was already known to the receiving party when received; (ii)
thereafter becomes lawfully obtainable from other sources through no act or
failure to act on the part of the receiving party; or (iii) is required to be
disclosed pursuant to applicable law, rules or regulations (including the
Securities Exchange Act of 1934, as amended and the rules and regulations
thereunder or the rules of any stock exchange), provided, that the receiving
party shall disclose only so much of the confidential information as is legally
required.

      8. MISCELLANEOUS.

      (a) All fees and expenses incurred in connection with this Agreement and
the transactions contemplated hereby, including all fees of counsel and
accountants, shall be paid by the party incurring the same.

      (b) All notices, requests, demands and other communications required or
permitted under this Agreement shall be in writing and shall be delivered
personally, sent facsimile transmission, or sent next-day delivery via Federal
Express or a similar overnight courier. All communications to Seller hereunder
should be sent to Crescent Real Estate Equities Limited Partnership, 777 Main
Street, Suite 2100, Ft. Worth, Texas 76102, Attn: Jason Anderson, telephone:
(817) 321-2100, facsimile: (817) 321-2050, with a copy to Sylvia M. Mahaffey,
Shaw Pittman, 2300 N Street, N.W., Washington, DC 20037, telephone: (202)
663-8000, facsimile: (202) 663-8007 or to such other person or address as Seller
shall furnish to Buyer in writing. All communications to Buyer hereunder should
be sent to Keystone Property Trust, 200 Four Falls Corporate Center, Suite 208,
West Conshohocken, Pennsylvania 19428, Attn: General Counsel, telephone: (484)
530-1800, facsimile: (484) 530-0131, with a copy to Clifford Chance Rogers &
Wells LLP, 200 Park Avenue, New York, NY 10166, Attn: Robert E. King, Jr., Esq.,
telephone: (212) 878-8000, facsimile: (212) 878-8375.

      A notice shall be deemed given for purposes of this Agreement (i) on the
date of delivery, if delivered personally or sent by facsimile transmission, and
(ii) on the first business day following the date of dispatch if sent next-day
delivery via Federal Express or similar a overnight courier. Any party may
change the address to which notices are to be sent by giving written notice of
such change of address to the other parties in the manner above provided for
giving notice.


      (c) THIS AGREEMENT SHALL BE CONSTRUED IN ACCORDANCE WITH AND GOVERNED BY
THE LAWS OF MARYLAND (WITHOUT GIVING EFFECT TO ANY CONFLICTS OR CHOICE OF LAWS
PROVISIONS THAT WOULD CAUSE THE APPLICATION OF THE DOMESTIC SUBSTANTIVE LAWS OF
ANY OTHER JURISDICTION).

      (d) This Agreement may not be amended, modified, superseded, cancelled,
renewed or extended except by a written instrument signed by both Buyer and
Seller; provided, that Buyer may assign its rights under this Agreement to the
Operating Partnership.

      (e) If any one or more of the covenants, agreements, provisions or terms
of this Agreement shall be held invalid, then such covenants, agreements,
provisions or terms shall be deemed severable from the remaining covenants,
agreements, provisions or terms of this Agreement and inoperative to the extent
it may conflict with any applicable statute or rule of law and shall be deemed
modified to conform

<PAGE>

with such statute or rule of law and shall in no way affect the validity or
enforceability of the other provisions of this Agreement or the rights of the
parties hereto.

      (f) This Agreement may be executed simultaneously in two or more identical
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.

      (g) EACH OF THE PARTIES HERETO HEREBY VOLUNTARILY AND IRREVOCABLY WAIVES
TRIAL BY JURY IN ANY ACTION OR OTHER PROCEEDING BROUGHT IN CONNECTION WITH THIS
AGREEMENT, ANY OF THE OTHER TRANSACTION DOCUMENTS OR ANY OF THE TRANSACTIONS
CONTEMPLATED HEREBY OR THEREBY.

      (h) Seller shall pay or cause to be paid all stamp, transfer or similar
taxes required to be paid in connection with the sale to the Buyer of the
Securities, and shall cause all appropriate stock transfer tax stamps to be
affixed to the certificates representing the Securities so sold and delivered.
The Seller shall file, independently or jointly with the Buyer, as the law
requires, all transfer tax filings required to be filed by it in connection with
the sale and delivery to the Buyer of the Securities.

      (i) Each party hereto further agrees that, at any time and from time to
time, upon the written request of the other party hereto, it will execute and
deliver such further instruments and do such further acts and things reasonably
necessary, desirable or proper as the requesting party may reasonably request in
order to effect the purposes of this Agreement.



<PAGE>



      IN WITNESS WHEREOF, the parties have executed this Agreement, acting by
their duly authorized agents, as of the date first above written.




KEYSTONE PROPERTY TRUST



By: /s/ Robert F. Savage Jr.
   -------------------------------
Name:  Robert F. Savage Jr.
Title: Executive Vice President and Chief Operating Officer



CRESCENT REAL ESTATE EQUITIES LIMITED PARTNERSHIP

By: Crescent Real Estate Equities, Ltd., its sole general partner



By: /s/ Jason E. Anderson
   -----------------------------
Name:  Jason E. Anderson
Title: Vice President, Investments


<PAGE>




                                    Exhibit A

                                   Securities

<TABLE>
<S>         <C>
1,693,471   Common Shares of Beneficial Interest of Keystone Property Trust
            represented by:


            Certificate:            Amount:

            K 0063                  5,493
            K 0058                  74,398
            K 0053                  1,207,021



            The balance of the shares (406,559) are in street name, are not
            certificated and were issued electronically through DTC's DWAC.



765,807     Units of Limited Partnership of Keystone Operating Partnership, L.P.
</TABLE>



<PAGE>



                                    Exhibit B



                                  Closing Dates



The initial Closing Date shall take place on April 27, 2001 and the Seller will
assign, sell, convey and transfer to Buyer in accordance with Section 1 of this
Agreement all right, title and interest of Seller in and to the 765,807 common
units of limited partnership in Keystone Operating Partnership, L.P. and 486,450
common shares (representing the uncertificated common shares and the common
shares represented by certificates K 0063 and K 0058) for an aggregate price of
$15,340,148.25 subject to a purchase price adjustment of $388,199.67 resulting
in a net payment to Seller from Buyer of $14,951,948.58.



The second Closing Date shall take place on May 1, 2001 and the Seller will
assign, sell, convey and transfer to Buyer in accordance with Section 1 of this
Agreement all right, title and interest of Seller in and to the 1,207,021 common
shares represented by certificate K 0053 for an aggregate price of
$14,786,007.25 subject to a purchase price adjustment of $374,176.51 resulting
in a net payment to Seller from Buyer of $14,411,830.74.