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                                                                   EXHIBIT 10.19

                         AGREEMENT OF PURCHASE AND SALE


      THIS AGREEMENT OF SALE AND ACQUISITION OF BENEFICIAL AND EQUITABLE
OWNERSHIP INTERESTS IN REAL PROPERTY ("AGREEMENT") made this 13th day of
September, 2001 between CLEARBROOK ROAD ASSOCIATES L.L.C., a limited
liability company duly organized, validly existing and in good standing under
the laws of the State of New York ("SELLER") having an address at c/o Chicago
Deferred Exchange Corporation, 171 North Clark Street, Ninth Floor, Chicago,
Illinois 60601 and MACK-CALI REALTY, L.P. a limited partnership duly organized,
validly existing and in good standing under the laws of the State of Delaware
("PURCHASER"), having an address at c/o Mack-Cali Realty Corporation 11 Commerce
Drive, Cranford, New Jersey 07016.

      WHEREAS, Purchaser desires to purchase and Seller desires to sell,
transfer and convey all of Seller's beneficial and equitable rights and
interests in and to approximately 4.239 acres of vacant land (the "Land") being
a part of certain real property known as 75 Clearbrook Road, Elmsford, New York
(the "75 Clearbrook Property") in accordance with the terms and conditions of
this Agreement;

      WHEREAS, pursuant to the terms of a certain Agreement of Sale and
Acquisition of Beneficial and Equitable Interests in Real Property dated as of
the date hereof, Seller acquired all beneficial and equitable rights and
interests in and to the Land from Robert Martin Company, LLC ("RMC");

      WHEREAS the parties acknowledge that pursuant to that certain Contribution
and Exchange Agreement (the "Contribution Agreement") dated January 24, 1997 by
and among RMC, together with one of its related entities, and Purchaser
(formerly known as Cali Realty, L.P.), together with its general partner
Mack-Cali Realty Corporation, (formerly known as Cali Realty Corporation), RMC
and Purchaser agreed and provided in the Contribution Agreement, that RMC
retained all of the beneficial and equitable interests and rights in and to the
Land and remained the beneficial owner thereof and that Purchaser would hold
legal title to the Land (but no beneficial, equitable or other interests or
rights in the Land whatsoever other than mere legal title thereto), solely in
its capacity as agent and nominee of RMC, for the sole and absolute benefit of
RMC;

      WHEREAS, Seller has assumed RMC's right and obligations under the
Contribution Agreement with respect to the Land and Purchaser, for all periods
from the time of execution of such agreement until the date and time hereof, has
adhered to the terms to the terms of the Contribution Agreement, and has served
and acted as RMC's, and now Seller's, agent and nominee for the sole and limited
purpose of acquiring and holding legal title to the Land for the sole and
absolute benefit of Seller and has taken only such actions with respect to such
Land during such periods as RMC or Seller has directed;

      WHEREAS, Purchaser is required by the terms of the Contribution Agreement
and has acknowledged and renewed its obligation to continue to act as Seller's
agent and nominee for the

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foregoing such limited purpose for all periods following the date hereof up and
to the moment of closing of the sale and conveyance of Seller's beneficial
interests and rights in and to the Land pursuant to this Agreement and to act
only in accordance with Seller's directions during such period.

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


                                    ARTICLE I
                                   DEFINITIONS

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

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

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

      "CLOSING DATE" means the date on which the Closing occurs, which will be
the date hereof. Notwithstanding the foregoing, Purchaser shall have the right
to accelerate the Closing on at least five (5) days notice to Seller, but which
notice shall not constitute a waiver by Purchaser of any obligations of Seller
hereunder which obligations will not have been performed by Seller by the date
set forth in Purchaser's acceleration notice, and which obligations shall
survive Closing.

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

      "CODE" has the meaning ascribed to such term in Section 10.3(d).

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

      "EFFECTIVE DATE" shall mean the date set forth in the opening paragraph of
this Agreement.

      "GOVERNMENTAL REGULATIONS" means all laws, ordinances, rules and
regulations of any governmental and quasi-governmental bodies or agencies
applicable to Seller, the Land, or any portion thereof, including without
limitation, the use, operation or construction of any of the foregoing.

      "IMPROVEMENTS" means all buildings, structures, fixtures, parking areas
and improvements located or to be constructed on the Land.

      "LAND" means approximately 4.239 acres of vacant land as shown on that
certain survey


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prepared for Cross Westchester Realty Associates L.P. in the Town of Greenburgh,
Westchester County, N.Y., dated February 1, 1997, prepared by Ward, Carpenter
Engineers, Inc., being a part of real property known as 75 Clearbrook Road,
located within the Cross Westchester Executive Park, located in Westchester
County, State of New York, as more particularly described on the legal
description attached hereto and made a part hereof as EXHIBIT A, together with
all of Seller's right, title and interest, if any, in and to the appurtenances
pertaining thereto, including but not limited to Seller's right, title and
interest in and to the adjacent streets, alleys and right-of-ways, and any
easement rights, air rights, subsurface development rights and water rights.

      "MANAGEMENT AGREEMENT" has the meaning ascribed to such term in Section
9.1.

      "PERMITTED EXCEPTIONS" has the meaning ascribed to such term in Section
6.1.

      "PERSONAL PROPERTY" means any and all furniture, fixtures, machinery and
equipment owned by Seller and situated on the Land and used in connection with
the ownership and operation thereof.

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

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

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

      SECTION 1.2 REFERENCES: EXHIBITS AND SCHEDULES. Except as otherwise
specifically indicated, all references in this Agreement to Articles or Sections
refer to Articles or Sections of this Agreement, and all references to Exhibits
or Schedules refer to Exhibits or Schedules attached hereto, all of which
Exhibits and Schedules are incorporated into, and made a part of, this Agreement
by reference. The words "herein," "hereof" "hereinafter" and words and phrases
of similar import refer to this Agreement as a whole and not to any particular
Section or Article.


                                   ARTICLE II
                      AGREEMENT OF PURCHASE AND ACQUISITION

      SECTION 2.1 AGREEMENT. In consideration of the payment of the Purchase
Price, Seller hereby agrees to sell, convey and assign to Purchaser, and
Purchaser hereby agrees to purchase, accept and assume from Seller, on the
Closing Date subject to the terms and conditions of this Agreement, all of the
Sellers rights and interests (beneficial, equitable or otherwise) in and to the
following (collectively, the "PROPERTY"):

                  (a) the Land

                  (b) the Improvements

                  (b) the Personal Property, if any;

                  (c) all of Seller's right, title and interest in and to all
intangible


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personal property used in connection with the ownership and operation of the
Land and/or the Improvements, including, without limitation, all plans,
specifications, warranties, permits, and licenses relating thereto;

                  (d) all of Seller's right, title and interest, to the extent
assignable or transferable, in and to all other intangible rights, titles,
interests, privileges and appurtenances owned by Seller and related to or used
exclusively in connection with the ownership, use or operation of the Land
and/or the Improvements; and

                  (e) any and all of Seller's rights, entitlements and claims of
any kind whatsoever under the Contribution Agreement with respect to the Land or
Purchaser's appointment as Seller's nominee and agent and agreement and
obligation to act as Seller's nominee and agent solely for purposes of holding
title to the Land and acting with respect thereto solely in accordance with
Seller's directions.

                  On the Closing Date, Purchaser and Seller shall agree to a
schedule setting forth the allocation of the Purchase Price to the Improvements,
and Personal Property, if any, or other items of the Property described in (c)
and (d) sold, conveyed and assigned to Seller hereunder, based on their
respective values.

      SECTION 2.2 RELATED AGREEMENTS. In addition to the sale of the Property
provided for in Section 2.1 and 2.2 hereof, Seller hereby agrees to assign and
transfer to Purchaser any and all warranties and guaranties, to the extent
assignable or transferable, which Seller may receive in connection with the
construction of the Improvements, together with any and all service contracts
and any other agreements affecting the Property (collectively, the "RELATED
AGREEMENTS"). In the event any of the Related Agreements are not assignable or
transferable, Seller hereby agrees to promptly enforce any such non-assignable
or non-transferable Related Agreements on Purchaser's behalf upon receipt of
request therefor from Purchaser. The obligations contained in this Section 2.2
shall survive the Closing Date.


                                   ARTICLE III
                                  CONSIDERATION

      SECTION 3.1 PURCHASE PRICE. The purchase price for the Property (the
"PURCHASE PRICE") shall be an amount equal to FIVE MILLION AND NO/100 DOLLARS,
($5,000,000.00) subject to adjustment as herein provided.

      SECTION 3.2 METHOD OF PAYMENT OF PURCHASE PRICE. No later than 1:00 p.m.
Eastern Standard Time on the Closing Date, Purchaser shall pay the Purchase
Price to Seller or as Seller otherwise directs, by bank check or Federal Reserve
wire transfer of immediately available funds, together with all other costs and
amounts to be paid by Purchaser at the Closing pursuant to the terms of this
Agreement.


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                                   ARTICLE IV
                 ACKNOWLEDGMENT OF CONSTRUCTION OF IMPROVEMENTS

      SECTION 4.1 APPROVAL OF PLANS. Purchaser hereby acknowledges that the
Improvements have not yet been constructed and that it has reviewed Seller's
preliminary plans for the construction of the Improvements and hereby approves
same (the "PLANS"). A schedule of the Plans is attached hereto as EXHIBIT B.
Seller shall not make any changes to the Plans without the express written
consent of Purchaser in each instance, which consent may be withheld or granted
in Purchaser's sole discretion.

      SECTION 4.2 COVENANT OF SELLER. Seller hereby covenants to Purchaser that
it shall construct all of the Improvements substantially in accordance with the
Plans and all applicable Governmental Regulations. Seller hereby acknowledges
and agrees that Seller's covenant to so construct the Improvements in
substantial accordance with the Plans is a material inducement to Purchaser
entering into this Agreement with Seller, and Purchaser shall not be obligated
to perform hereunder unless and until the Improvements are in a phase of
Substantial Completion and have been constructed in substantial accordance with
the Plans. Notwithstanding the foregoing, Purchaser shall have the right, but
not the obligation, to waive the requirements of this Article 4 and proceed with
the Closing regardless of whether Seller has constructed the Improvements in
substantial accordance with the Plans.



                                    ARTICLE V
                              SALE AS-IS, WHERE-IS

      SECTION 5.1 SALE "AS IS".

            (a) EXCEPT AS OTHERWISE SPECIFICALLY STATED IN THIS AGREEMENT TO THE
CONTRARY, SELLER HEREBY SPECIFICALLY DISCLAIMS ANY WARRANTY, GUARANTY OR
REPRESENTATION, ORAL OR WRITTEN, PAST, PRESENT OR FUTURE OF, AS TO, OR
CONCERNING: (I) THE NATURE AND CONDITION OF THE PROPERTY, INCLUDING WITHOUT
LIMITATION (A) THE WATER, SOIL AND GEOLOGY AND THE SUITABILITY THEREOF, AND OF
THE PROPERTY FOR ANY AND ALL ACTIVITIES AND USES WHICH PURCHASER MAY ELECT TO
CONDUCT THEREON, (B) THE EXISTENCE OF ANY ENVIRONMENTAL HAZARDS OR CONDITIONS
THEREON (INCLUDING BUT NOT LIMITED TO THE PRESENCE OF ASBESTOS OR THE RELEASE OR
THREATENED RELEASE OF HAZARDOUS SUBSTANCES) AND (C) COMPLIANCE WITH ALL
APPLICABLE LAWS, RULES OR REGULATIONS; (II) THE NATURE AND EXTENT OF ANY
RIGHT-OF-WAY, LEASE, POSSESSION, LIEN, ENCUMBRANCE, LICENSE, RESERVATION,
CONDITION OR OTHERWISE; (III) THE COMPLIANCE OF THE PROPERTY OR ITS OPERATION
WITH ANY LAWS, ORDINANCES OR REGULATIONS OF ANY GOVERNMENT OR OTHER BODY AND
(IV) THE ACCURACY OR COMPLETENESS OF ANY DOCUMENT SUPPLIED TO PURCHASER AS PART
OF THE PURCHASER'S INSPECTION, OR OTHERWISE. PURCHASER FURTHER ACKNOWLEDGES THAT
THE INFORMATION PROVIDED WITH RESPECT TO THE PROPERTY WAS OBTAINED FROM A
VARIETY


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OF SOURCES AND, EXCEPT AS SPECIFICALLY STATED IN THIS AGREEMENT, SELLER (X) HAS
NOT MADE ANY INDEPENDENT INVESTIGATION OR VERIFICATION OF SUCH INFORMATION AND
(Y) DOES NOT MAKE ANY REPRESENTATIONS AS TO THE ACCURACY OR COMPLETENESS OF SUCH
INFORMATION. EXCEPT AS OTHERWISE SPECIFICALLY STATED IN THIS AGREEMENT, THE SALE
OF THE PROPERTY AS PROVIDED FOR HEREIN IS MADE ON AN "AS IS, WHERE IS, WITH ALL
FAULTS" BASIS, AND PURCHASER EXPRESSLY ACKNOWLEDGES THAT, IN CONSIDERATION OF
THE AGREEMENTS OF SELLER HEREIN, SELLER MAKES NO WARRANTY OR REPRESENTATION,
EXPRESS OR IMPLIED, OR ARISING BY OPERATION OF LAW, INCLUDING, BUT NOT LIMITED
TO, ANY WARRANTY OF CONDITION, HABITABILITY, MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE, IN RESPECT OF THE PROPERTY OR OTHERWISE.

            (b) Except as expressly set forth in this Agreement, including
without limitation Seller's obligation to construct the Improvements
substantially in accordance with the Plans as set forth in Section 4.2 hereof,
Purchaser agrees that Seller shall not be responsible or liable to Purchaser for
any construction defect, errors or omissions in the design or construction of
the Improvements or any other conditions, including environmental conditions
affecting the Property, such as the presence of asbestos, petroleum products or
other hazardous substances or contamination of the Property by a release of
hazardous substances, pollutants, contaminants or petroleum products and
Purchaser is purchasing the Property AS-IS, WHERE-IS and WITH ALL FAULTS.


                                   ARTICLE VI
                               CONDITION OF TITLE

      SECTION 6.1 CONDITION OF TITLE. Attached hereto as EXHIBIT B is a complete
list of all liens and encumbrances encumbering the Land and the Improvements
existing on the date hereof (the "PERMITTED EXCEPTIONS"). Notwithstanding
anything to the contrary contained in Article 5 hereof, Seller shall sell,
convey and assign to Purchaser the Property subject only to the Permitted
Exceptions. In furtherance of the foregoing, Seller shall not place any lien or
encumbrance upon the Property, including without limitation any mortgage liens
or other liens used to secure debt, from and after the date hereof without the
express written consent of Purchaser, which consent may be withheld or granted
in Purchaser's sole discretion. If on the Closing Date there exists liens or
encumbrances on the Property other than the Permitted Exceptions and other than
liens or encumbrances placed upon the Property by or as a result of the actions
of MCRLP, Purchaser shall have the option to either (i) waive the provisions of
this Section 6.1 and proceed with the Closing with an adjustment to the Purchase
Price equal to an amount Seller and Purchaser reasonably agree shall be
necessary to remove such additional liens or encumbrances, or (ii) postpone the
Closing for such time as may be necessary for Seller to remove such additional
liens or encumbrances. In the event Purchaser elects to postpone the Closing as
herein provided, if Seller does not provide Purchaser with written notice that
such additional liens or encumbrances have been removed within sixty (60) days
from the originally scheduled Closing Date, Purchaser shall have the right, as
its sole and exclusive remedy, to terminate this Agreement upon written notice
to Seller.


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                                   ARTICLE VII
                         REPRESENTATIONS AND WARRANTIES

      SECTION 7.1 SELLER'S REPRESENTATIONS AND WARRANTIES. The following
constitute the sole representations and warranties of Seller which
representations and warranties shall be true as of the Effective Date. Seller
represents and warrants to Purchaser the following:

                  (a) STATUS. Seller is a limited liability company duly
organized and validly existing under the laws of the State of New York.

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

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

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

                  (e) LAND. Seller is currently the sole owner of the beneficial
and equitable rights and interests in the Land.

                  (f) IMPROVEMENTS. Seller shall be the sole owner of the
Improvements at all times until Seller transfers ownership of the Improvements
to Purchaser pursuant to this Agreement.

      SECTION 7.2 PURCHASER'S REPRESENTATIONS AND WARRANTIES. Purchaser
represents and warrants to Seller the following:

                  (a) STATUS. Purchaser is a limited partnership duly organized
and validly existing under the laws of the State of Delaware.

                  (b) AUTHORITY. The execution and delivery of this Agreement
and the performance of Purchaser's obligations hereunder have been or will be
duly authorized by all necessary action on the part of Purchaser and this
Agreement constitutes the legal, valid and binding obligation of Purchaser,
subject to equitable principles and principles governing creditor's rights
generally.


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

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


                                  ARTICLE VIII
                            CONDEMNATION AND CASUALTY

      SECTION 8.1 CASUALTY.

                  (a) On or before the date Seller commences construction of the
Improvements Seller shall obtain, and Seller shall maintain until the Closing
Date, fire and extended coverage insurance policies with respect to the Property
(the "POLICY") in an amount and with deductibles reasonably acceptable to
Purchaser.

                  (b) If at any time prior to the Closing Date any portion of
the Improvements is destroyed or damaged as a result of fire or any other
casualty (a "CASUALTY"), Seller shall promptly give written notice ("CASUALTY
NOTICE") thereof to Purchaser. If the Casualty shall prevent the acquisition of
the Improvements or adversely impact Purchaser's ability to use the
Improvements, then within thirty (30) days after the receipt of the Casualty
Notice, Purchaser shall have the right, at its sole option, of terminating this
Agreement by written notice to Seller. Should Purchaser so terminate this
Agreement in accordance with this Section, neither party shall have any further
liability or obligations to the other, other than those which are expressly
stated herein to survive any such termination. In the event Purchaser elects not
to terminate this Agreement as herein provided and the Closing is scheduled to
occur prior to the date Seller completes the repairs and restorations required
due to such Casualty, the proceeds of any insurance with respect to the
Improvements paid between the date of this Agreement and the Closing Date and
not applied by Seller in the performance of any repairs or restorations of such
Casualty, plus the amount of Seller's deductible under the policy insuring the
Casualty, shall be paid to Purchaser at Closing, and all unpaid claims and
rights in connection with losses to the Property shall be assigned to Purchaser
at Closing without in any manner affecting the Purchase Price.

      SECTION 8.2 CONDEMNATION OF PROPERTY. In the event of any condemnation or
sale in lieu of condemnation of all or any portion of the Property Seller will
assign to Purchaser any and all claims for the proceeds of such condemnation or
sale to the extent the same are applicable to the Property, and Purchaser will
take title to the Property with the assignment of such proceeds


                                       8
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and subject to such condemnation and without reduction of the Purchase Price.


                                   ARTICLE IX
                              MANAGEMENT AGREEMENT

      SECTION 9.1 MANAGEMENT AGREEMENT. On or before the date Seller completes
construction of the Improvements, Seller and Purchaser shall enter into an
agreement providing for the management and operation of the Improvements by
Purchaser (the "MANAGEMENT AGREEMENT"). Such Management Agreement shall be on
terms mutually and reasonably acceptable to both Seller and Purchaser. The
Management Agreement shall be for a term commencing on the date Seller completes
construction of the Improvements and expiring on the Closing Date.


                                    ARTICLE X
                                     CLOSING

      SECTION 10.1 CLOSING. The consummation of the transaction contemplated by
this Agreement by delivery of documents and payments of money shall take place
10:00 a.m. on the Closing Date at the offices of Pryor Cashman Sherman & Flynn
LLP, 410 Park Avenue, 10th Floor, New York, New York 10022. At Closing, the
events set forth in this Article X will occur, it being understood that the
performance or tender of performance of all matters set forth in this Article X
are mutually concurrent conditions which may be waived by the party for whose
benefit they are intended. The acceptance of the Deed and other closing
documents required hereunder by Purchaser shall be deemed to be full performance
and discharge of each and every agreement and obligation on the part of the
Seller to be performed hereunder.

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

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

                  (b) A counterpart original of an assignment and assumption
agreement of the Related Agreements in a form reasonably and mutually acceptable
to Seller and Purchaser, duly executed by Purchaser, providing for the
assignment and assumption of the Related Agreements as contemplated in Article
II hereof, which assignment shall be effective as of the Closing Date (the
"ASSIGNMENT AND ASSUMPTION OF RELATED AGREEMENTS");

                  (c) A counterpart original of the Closing Statement (as
hereinafter defined), duly executed by Purchaser;

                  (d) Counterpart originals of the transfer tax returns, each
duly executed by Purchaser; and


                                       9
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                  (e) Such other documents as may be reasonably necessary or
appropriate to effect the consummation of the transaction with is the subject of
this Agreement.

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

                  (a) A Transfer Document (the "CONVEYANCE DOCUMENT"), duly
executed and acknowledged by Seller, conveying to the Purchaser all of Seller's
beneficial, equitable and other rights, benefits and interests in and to the
Property subject only to the Permitted Exceptions;

                  (b) A counterpart original of the Assignment and Assumption of
Related Agreements;

                  (c) Counterparts of the transfer tax returns, duly executed by
Seller, together with any payments due in connection therewith;

                  (d) A certificate signed by the managing member or officer of
Seller to the effect that seller is not a "foreign person" as that term is
defined in Section 1445(f)(3) of the Internal Revenue Code of 1986, as amended
(the "CODE"), in order to avoid the imposition of the withholding tax payment
pursuant to Section 1445 of the Code.

                  (e) All leases, licenses, files and all other documents in
Seller's possession or control relating to the Property; and

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

      SECTION 10.4 OPTION TO REQUEST DELIVERY OF LLC INTEREST. Purchaser shall
have the right to direct CDECRE, Inc.("CDECRE"), an Illinois corporation and the
sole owner of the entire membership interest in Seller (the "LLC INTEREST"), to
transfer, assign, convey and deliver the LLC Interest to Purchaser at the
Closing, pursuant to an assignment of interests in limited liability company
with typical representations and warranties and in form and substance
satisfactory to Purchaser (the "ASSIGNMENT"), in lieu of the Conveyance Document
described in Section 10.3(a). Upon the delivery of the Assignment by CDECRE at
the Closing and acceptance thereof by Purchaser, Seller shall be relieved of any
further obligation under Section 10.3(a).

      SECTION 10.5 PRORATIONS. Seller and Purchaser agree to adjust, as of 11:59
p.m. on the day preceding the Closing Date (the "PRORATION TIME"), the real
estate and personal property taxes and assessments payable by the owner of the
Property (collectively, the "PRORATION ITEMS"). Seller will be charged and
credited for the amounts of all of the Proration Items relating to the period up
to and including the Proration Time, and Purchaser will be charged and credited
for all of the Proration Items relating to the period after the Proration Time.
Such preliminary estimated Closing prorations shall be set forth on a
preliminary closing statement to be prepared by Purchaser and submitted to
Seller for Seller's approval prior to the Closing Date (the "CLOSING
STATEMENT"). The Closing Statement, once agreed upon, shall be signed by
Purchaser


                                       10
<Page>

and Seller. The proration herein contemplated shall be paid at Closing by
Purchaser to Seller (if the preliminary prorations result in a net credit to
Seller) or by Seller to Purchaser (if the preliminary prorations result in a net
credit to Purchaser) by increasing or reducing the cash to be delivered by
Purchaser in payment of the Purchase Price at the Closing. If the actual amounts
of the Proration Items are not known as of the Closing Date, the prorations will
be made at Closing on the basis of the best evidence then available; thereafter,
when actual figures are received, re-prorations will be made on the basis of the
actual figures, and a final cash settlement will be made between Seller and
Purchaser. No prorations will be made in relation to insurance premiums, and
Seller's insurance policies will not be assigned to Purchaser.

      SECTION 10.6 ADJUSTMENTS TO PURCHASE PRICE. In addition to the Prorated
Items, in the event the total amount of financing obtained by Seller for the
construction of the Improvements (the "CONSTRUCTION FINANCING") is greater than
the Purchase Price, the Purchase Price shall be increased by an amount equal to
the difference between the Construction Financing and the Purchase Price.
Conversely, if the Construction Financing is less than the Purchase Price, the
Purchase Price shall be reduced by an amount equal to the difference between the
Construction Financing and the Purchase Price.

      SECTION 10.7 DELIVERY OF PROPERTY. Upon completion of the Closing, Seller
will deliver to Purchaser possession of the Property and the Land, subject only
to the Permitted Exceptions.

      SECTION 10.8 CLOSING COSTS. Closing costs incurred in connection with the
Closing will be allocated as follows:

                  (a) Seller shall pay all New York real estate transfer tax
fees due in connection with the Closing.

                  (b) Purchaser shall pay Seller's attorney's fees.

                  (c) Purchaser shall pay the costs of recording any instruments
required in connection with the Closing and Purchaser's attorney's fees.

                  (d) Any other costs and expenses of Closing not provided for
in this Section 10.7 shall be allocated between Purchaser and Seller in
accordance with the custom of Westchester County, New York.

                  (e) If the Closing does not occur on or before the Closing
Date for any reason whatsoever, the costs incurred through the date of
termination will be borne by the party incurring same.


                                   ARTICLE XI
                                    REMEDIES

      SECTION 11.1 DEFAULT BY SELLER. In the event the Closing and the
transactions contemplated hereby do not occur as herein provided by reason of
any default of Seller,


                                       11
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Purchaser may exercise any and all rights and remedies available to Purchaser at
law or in equity, including, without limitation, the right to (a) terminate this
Agreement, whereupon Seller and Purchaser will have no further rights or
obligations under this Agreement; or (b) seek to enforce specific performance of
this Agreement.

      SECTION 11.2 DEFAULT BY PURCHASER. In the event the closing and the
consummation of the transactions contemplated herein do not occur as provided
herein by reason of any default of Purchaser, Seller may exercise any and all
rights and remedies available to Seller at law or in equity, including, without
limitation, the right to seek to enforce specific performance of the Agreement.
Notwithstanding anything to the contrary contained herein, in no event shall
Seller have the right to terminate this Agreement on account of Purchaser's
default hereunder.


                                   ARTICLE XII
                                     NOTICES

      SECTION 12.1 NOTICES. All notices or other communications required or
permitted hereunder will be in writing, and will be given by (a) personal
delivery, or (b) professional expedited delivery service with proof of delivery,
or (c) United States mail, postage prepaid, registered or certified mail, return
receipt requested, or (d) prepaid telegram, facsimile or telex (providing that
such telegram, facsimile or telex is confirmed by the sender by expedited
delivery service or by mail in the manner previously described), or (e) sent by
a nationally recognized overnight courier service, sent to the intended
addressee at the address set forth below, or to such other address or to the
attention of such other person as the addressee will have designated by written
notice sent in accordance herewith and will be deemed to have been given either
at the time of delivery or refusal to accept delivery. Unless changed in
accordance with the preceding sentence, the addresses for notices given pursuant
to this Agreement will be as follows:

      If to Purchaser:  Mack-Cali Realty, L.P.
                        c/o Mack-Cali Realty Corporation
                        11 Commerce Drive
                        Cranford, New Jersey  07016
                        Attn.:   Roger W. Thomas, Esq.
                                 Executive Vice President and General Counsel
                        (908) 272-8000  (tele.)
                        (908) 497-0485  (fax)


      with a copy to:   Pryor Cashman Sherman & Flynn LLP
                        410 Park Avenue, 10th Floor
                        New York, New York 10022
                        Attn.:  Stephen G. Epstein, Esq.
                        (212) 326-0486  (tele.)
                        (212) 326-0806  (fax)


                                       12
<Page>

      If to Seller:     Clearbrook Road Associates L.L.C.
                        c/o Chicago Deferred Exchange Corporation
                        171 North Clark Street
                        Chicago, IL  60601
                        Attn:  Miriam Golden, Esq
                        (312) 223-3494 (tele.)
                        (312) 223-3301 (fax)


       and              CDECRE, Inc.
                        c/o Chicago Deferred Exchange Corporation
                        171 North Clark Street
                        Chicago, IL  60601
                        Attn: Miriam Golden, Esq.
                        (312) 223-3394 (tele.)
                        (312) 223-3301 (fax)


                                  ARTICLE XIII
                          ASSIGNMENT AND BINDING EFFECT

      SECTION 13.1 ASSIGNMENT: BINDING EFFECT. Purchaser and Seller shall both
have the right to assign this Agreement without the other's prior written
consent to an entity controlled by or under common control with Purchaser or
Seller, as applicable. This Agreement will be binding upon and inure to the
benefit of Seller and Purchaser and their respective successors and permitted
assigns, and no other party will be conferred any rights by virtue of this
Agreement or be entitled to enforce any of the provisions hereof. Whenever a
reference is made in this Agreement to Seller or Purchaser, such reference will
include the successors and permitted assigns of such party under this Agreement.


                                  ARTICLE XIV
                                 MISCELLANEOUS

      SECTION 14.1 WAIVERS. No waiver of any breach of any covenant or
provisions contained herein will be deemed a waiver of any preceding or
succeeding breach thereof, or of any other covenant or provision contained
herein. No extension of time for performance of any obligation or act will be
deemed an extension of the time for performance of any other obligation or act.

      SECTION 14.2 RECOVERY OF CERTAIN FEES. In the event a party hereto files
any action or suit against another party hereto by reason of any breach of any
of the covenants, agreements or provisions contained in this Agreement, then in
that event the prevailing party will be entitled to have and recover certain
fees from the other party including all attorneys' fees and costs resulting
therefrom. For purposes of this Agreement, the term "attorneys' fees" or
"attorneys' fees and costs" shall mean the fees and expenses of counsel to the
parties hereto, which may include printing, photostating, duplicating and other
expenses, air freight charges, and fees billed for law


                                       13
<Page>

clerks, paralegals and other persons not admitted to the bar but performing
services under the supervision of an attorney, and the costs and fees incurred
in connection with the enforcement or collection of any judgment obtained in any
such proceeding. The provisions of this Section 14.2 shall survive the entry of
any judgment, and shall not merge, or be deemed to have merged, into any
judgment.

      SECTION 14.3 TIME OF ESSENCE. Seller and Purchaser hereby acknowledge and
agree that time is strictly of the essence with respect to each and every term,
condition, obligation and provision hereof.

      SECTION 14.4 CONSTRUCTION. Headings at the beginning of each article and
section are solely for the convenience of the parties and are not a part of this
Agreement. Whenever required by the context of this Agreement, the singular will
include the plural and the masculine will include the feminine and vice versa.
This Agreement will not be construed as if it had been prepared by one of the
parties, but rather as if both parties had prepared the same. All exhibits and
schedules referred to in this Agreement are attached and incorporated by this
reference, and any capitalized term used in any exhibit or schedule which is not
defined in such exhibit or schedule will have the meaning attributable to such
term in the body of this Agreement. In the event the date on which Purchaser or
Seller is required to take any action under the terms of this Agreement is not a
Business Day, the action will be taken on the next succeeding Business Day.

      SECTION 14.5 COUNTERPARTS. To facilitate execution of this Agreement, this
Agreement may be executed in multiple counterparts, each of which, when
assembled to include an original signature for each party contemplated to sign
this Agreement, will constitute a complete and fully executed original. All such
fully executed original counterparts will collectively constitute a single
agreement.

      SECTION 14.6 SEVERABILITY. If any term or other provision of this
Agreement is invalid, illegal, or incapable of being enforced by any rule of law
or public policy, all of the other conditions and provisions of this Agreement
will nevertheless remain in full force and effect, so long as the economic or
legal substance of the transactions contemplated hereby is not affected in any
adverse manner to either party. Upon such determination that any term or other
provision is invalid, illegal, or incapable of being enforced, the parties
hereto will negotiate in good faith to modify this Agreement so as to reflect
the original intent of the parties as closely as possible in an acceptable
manner to the end that the transactions contemplated hereby are fulfilled to the
extent possible.

      SECTION 14.7 ENTIRE AGREEMENT. This Agreement is the final expression of,
and contains the entire agreement between, the parties with respect to the
subject matter hereof, and supersedes all prior understandings with respect
thereto. This Agreement may not be modified, changed, supplemented or
terminated, nor may any obligations hereunder be waived, except by written
instrument, signed by the party to be charged or by its agent duly authorized in
writing, or as otherwise expressly permitted herein.

      SECTION 14.8 GOVERNING LAW. THIS AGREEMENT WILL BE CONSTRUED, PERFORMED
AND ENFORCED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK.


                                       14
<Page>

      SECTION 14.9 NO RECORDING. The parties hereto agree that neither this
Agreement nor any affidavit concerning it will be recorded and any recording of
this Agreement by Purchaser will be deemed an event of default hereunder.

      SECTION 14.10 FURTHER ACTIONS. The parties agree to execute such other
instruments and to do such further acts as may be reasonably necessary to carry
out the provisions of this Agreement.

      SECTION 14.11 NO OTHER INDUCEMENTS. The making, execution and delivery of
this Agreement by the parties hereto has been induced by no representations,
statements, or warranties except as set forth herein.

      SECTION 14.12 EXHIBITS. Exhibits A through C attached hereto are
incorporated herein by reference.

      SECTION 14.13 NO PARTNERSHIP. Notwithstanding anything to the contrary
contained herein, this Agreement shall not be deemed or construed to make the
parties hereto partners or joint venturers, it being the intention of the
parties to merely create the relationship of seller and purchaser with respect
to the Property to be conveyed as contemplated hereby.

      SECTION 14.14 LIMITATIONS ON BENEFITS. It is the explicit intention of
Purchaser and Seller that no person or entity other than Purchaser and Seller
and their permitted successors and assigns is or shall be entitled to bring any
action to enforce any provision of this Agreement against any of the parties
hereto, and the covenants, undertakings and agreements set forth in this
Agreement shall be solely for the benefit of, and shall be enforceable only by,
Purchaser and Seller or their respective successors and assigns as permitted
hereunder. Nothing contained in this Agreement shall under any circumstances
whatsoever be deemed or construed, or be interpreted, as making any third party
a beneficiary of any term or provision of this Agreement or any instrument or
document delivered pursuant hereto, and Purchaser and Seller expressly reject
any such intent, construction or interpretation of this Agreement.


                                       15
<Page>

      IN WITNESS WHEREOF, Seller and Purchaser have respectively executed this
Agreement to be effective as of the date first above written.

                              SELLER:

                              CLEARBROOK ROAD ASSOCIATES L.L.C, a
                              New York limited liability company

                              By:  CDECRE, Inc., an Illinois corporation


                                    by: /s/ Mary Cunningham
                                       ------------------------------
                                       Name:  Mary Cunningham
                                       Title:


                              PURCHASER:

                              MACK-CALI REALTY, L.P., a Delaware limited
                              Partnership

                              By: Mack-Cali Realty Corporation, a Maryland
                                  corporation, its general partner


                                 by: /s/ Roger W. Thomas
                                    ---------------------------------
                                    Name:  Roger W. Thomas
                                    Title: Executive Vice President &
                                             General Counsel

                              Agreed to and Accepted as to
                              Section 10.4 hereof only

                              CDECRE, Inc., an Illinois corporation


                              By: /s/ Karen Cholipski
                                 ------------------------------------
                                 Name: Karen Cholipski
                                 Title: