Document:

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                                                                 EXHIBIT 4.8

                       REGULATION D SUBSCRIPTION AGREEMENT

         THE SECURITIES OFFERED HEREBY HAVE NOT BEEN REGISTERED WITH THE
         SECURITIES AND EXCHANGE COMMISSION OR ANY STATE OR OTHER SECURITIES
         AUTHORITIES. THEY MAY NOT BE SOLD OR TRANSFERRED EXCEPT PURSUANT TO AN
         EFFECTIVE REGISTRATION STATEMENT OR AN EXEMPTION TO THE REGISTRATION
         REQUIREMENTS OF THOSE SECURITIES LAWS.

         THIS SUBSCRIPTION AGREEMENT DOES NOT CONSTITUTE AN OFFER TO SELL, OR A
         SOLICITATION OF AN OFFER TO PURCHASE, ANY OF THE SECURITIES DESCRIBED
         HEREIN BY OR TO ANY PERSON IN ANY JURISDICTION IN WHICH SUCH OFFER OR
         SOLICITATION WOULD BE UNLAWFUL. THESE SECURITIES HAVE NOT BEEN
         RECOMMENDED BY ANY FEDERAL, STATE OR FOREIGN SECURITIES AUTHORITIES,
         NOR HAVE ANY SUCH AUTHORITIES REVIEWED OR DETERMINED THE ACCURACY OF
         THIS DOCUMENT. ANY REPRESENTATION TO THE CONTRARY IS UNLAWFUL.

         INVESTMENT IN THESE SECURITIES INVOLVES A HIGH DEGREE OF RISK,
         INCLUDING BUT NOT LIMITED TO THOSE RISK FACTORS IDENTIFIED IN THE
         COMPANY'S FORM S-3 FILED ON NOVEMBER 17, 2000 WITH THE SECURITIES AND
         EXCHANGE COMMISSION. INVESTORS MUST RELY ON THEIR OWN ANALYSIS OF THE
         INVESTMENT TERMS AND CONDITIONS OF THE PROPOSED INVESTMENT AND THEIR
         OWN ASSESSMENT OF THE RISKS INVOLVED.

         This Regulation D Subscription Agreement (the "Agreement") is executed
by the undersigned (the "Subscriber") in connection with the offer to the
Subscriber of, and the subscription by the Subscriber for, shares of Common
Stock, $.001 par value per share (the "Common Stock"), of SI DIAMOND TECHNOLOGY,
INC., a Texas corporation (the "Company"). The Company shall sell to the
Subscriber _________ shares of the Company's Common Stock at a price of $______
per share, for an aggregate purchase price of $________ .

         The solicitation of this Subscription by the Company, and if accepted
by the Company, the sale of the shares of Common Stock subscribed for, are being
made on reliance upon the provisions of Regulation D ("Regulation D")
promulgated under the Securities Act of 1933 (the "Securities Act").

         The undersigned Subscriber and the Company, upon acceptance of this
Agreement, hereby agree as follows:
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         1.       Offering

                  1.1      Offer to Subscribe; Purchase Price and Closing; and
Placement Fees. Subject to satisfaction of the conditions to the closing of a
purchase and sale of Common Stock as to each purchaser of Common Stock (the
"Closing") set forth in Section 1.2 below, the Subscriber hereby offers to
subscribe for and purchase shares of Common Stock, for the aggregate purchase
price set forth in Section 8 of this Agreement, all in accordance with the terms
and conditions of this Agreement. The Closing shall be deemed to occur when this
Agreement has been executed by both the Subscriber and the Company, and full
payment for the shares of Common Stock subscribed for shall have been made by
the Subscriber, by wire transfer in United States Dollars, to the Company as set
forth in Section 7.1(a) in consideration for the Company's delivery of
certificates representing the shares of Common Stock so subscribed for.

                  1.2      Conditions to Subscriber's Obligations. The
Subscriber's obligations hereunder are conditioned upon the occurrence of all of
the following:

                           (a)      other than as described on Schedule 1.2
                                    attached hereto, there have been no material
                                    adverse changes in the Company's business
                                    prospects or financial condition since the
                                    date of the last balance sheet included in
                                    the Disclosure Documents (as defined below
                                    in Section 4.2);

                           (b)      the representations and warranties of the
                                    Company shall be true and correct in all
                                    material respects on the date of Closing, as
                                    if made on such date, and the Company shall
                                    deliver a certificate, signed by an officer
                                    of the Company, to such effect; and

                           (c)      the Subscription Agreement has been accepted
                                    by the Company.

         2.       Representations and Warranties of the Subscriber. The
Subscriber hereby represents and warrants to the Company as follows (which
representations and warranties shall be true as of the date of Closing):

                  2.1      Accredited Investor. The Subscriber hereby represents
and warrants to the Company that it is an "accredited investor," as defined in
Rule 501 of Regulation D, and has marked the applicable box set forth in Section
9 of this Agreement signifying such status.

                  2.2      Investment Experience; Access to Information;
Independent Investigation.

                           2.2.1    Access to Information. The Subscriber or its
professional advisor has been granted the opportunity to ask questions of and
receive answers from representatives of the Company, and its officers,
directors, employees and agents concerning the terms and conditions of the
Offering, and the Company and its business and prospects, and to obtain any
additional information which the Subscriber or its professional advisor deems
necessary to verify the accuracy of the information received. The foregoing,
however, does not limit or modify the

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Subscriber's right to rely upon representations and warranties of the Company in
Section 4 of this Agreement.

                           2.2.2    Ability to Evaluate. The Subscriber has such
knowledge and experience in financial and business matters that it is fully
capable of evaluating the merits and risks of an investment in the Company,
including without limitation those set forth in the Disclosure Documents (as
defined below in Section 4.2).

                           2.2.3    Disclosure Documents. The Subscriber has
received and reviewed the Disclosure Documents (as defined below in Section
4.2). The foregoing, however, does not limit or modify the Subscriber's right to
rely upon the representations and warranties of the Company in Section 4 of this
Agreement.

                           2.2.4    Investment Experience; Fend for Self. The
Subscriber has substantial experience in investing in securities and has made
investments in securities other than those of the Company. The Subscriber
acknowledges that it is able to fend for itself in the transaction contemplated
by this Agreement and that it has the ability to bear the economic risk of its
investment in the Company. The Subscriber has not been organized for the purpose
of investing in securities of the Company.

                           2.2.5    Not an Affiliate. The Subscriber is not an
officer, director or "affiliate" (as that term is defined in Rule 415 of the
Securities Act) of the Company.

                  2.3      Exempt Offering Under Regulation D

                           2.3.1    Investment; No Distribution. The Subscriber
is acquiring the shares of Common Stock subscribed for (the "Common Shares")
solely for investment purposes for the Subscriber's own account (or for
beneficiaries' accounts over which the Subscriber has investment discretion but
no discretionary authority as to voting or disposition) and not with a view to a
distribution of all or any part thereof. The Subscriber is aware that there are
legal and practical limits on its ability to sell or dispose of the Common
Shares and therefore, that the Subscriber must bear the economic risk of its
investment for an indefinite period of time. The Subscriber has adequate means
of providing for its current needs and anticipated contingencies and has no need
for liquidity of this investment. The Subscriber's commitment to illiquid
investments is reasonable in relation to its net worth.

                           2.3.2    No General Solicitation. The Common Shares
were not offered to the Subscriber through, and the Subscriber is not aware of,
any form of general solicitation or general advertising, including, without
limitation, (i) any advertisement, articles, notice or other communication
published in any newspaper, magazine or similar media or broadcast over
television or radio, and (ii) any seminar or meeting whose attendees have been
invited by any general solicitation or general advertising.

                           2.3.3    No Registration of Common Shares. The
Subscriber understands that the Common Shares are not registered and therefore
are "restricted securities" under the

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federal securities laws inasmuch as they are being acquired from the Company in
a transaction not involving a public offering, and that, under such laws and
applicable regulations, such securities may not be transferred or resold without
registration under the Securities Act or pursuant to an exemption therefrom. In
this connection, the Subscriber represents that it is familiar with Rule 144
under the Securities Act, as presently in effect, and understands the resale
limitations imposed thereby and by the Securities Act.

                           2.3.4    Disposition. Without in any way limiting the
representations set forth above, the Subscriber further agrees not to make any
disposition of all or any portion of the Securities unless and until:

                                    (a)     There is then in effect a
                                            registration statement under the
                                            Securities Act covering such
                                            proposed disposition and such
                                            disposition is made in accordance
                                            with such Registration Statement; or

                                    (b)     The Subscriber shall have notified
                                            the Company of the proposed
                                            disposition and shall have furnished
                                            the Company with a detailed
                                            statement of the circumstances
                                            surrounding the proposed
                                            disposition, and (ii) if reasonably
                                            requested by the Company, the
                                            Subscriber shall have furnished the
                                            Company with an opinion of counsel,
                                            reasonably satisfactory to the
                                            Company, that such disposition will
                                            not require registration of the
                                            Common Shares under the Securities
                                            Act.

                  2.4      Due Authorization.

                           2.4.1    Authority. The Subscriber, if executing this
Subscription Agreement in a representative or fiduciary capacity, has full power
and authority to execute and deliver this Subscription Agreement and each other
document referred to herein for which a signature is required in such capacity
and on behalf of the subscribing individual, partnership, trust, estate,
corporation or other entity for whom or which the Subscriber is executing this
Subscription Agreement.

                           2.4.2    Due Authorization. The Subscriber, if an
entity, is duly and validly organized, validly existing and in good standing as
such entity under the laws of the jurisdiction of its organization, with full
power and authority to purchase the Common Shares subscribed for and to execute
and deliver this Agreement.

         3.       Acknowledgments. The Subscriber is aware of the following:

                  3.1      Risks of Investment. The Subscriber recognizes that
investment in the Company involves certain risks, including the potential loss
of the Subscriber's investment herein. The Subscriber recognizes that this
Agreement and the exhibits hereto do not purport to

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contain all the information which would be contained in a registration statement
under the Securities Act;

                  3.2      No Government Approval. The Subscriber acknowledges
that no federal, state or foreign agency has passed upon or reviewed the terms
and conditions of the Offering or made any finding or determination as to the
fairness of the Offering;

                  3.3      Restrictions on Transfer. The Subscriber may not
sell, transfer, assign, pledge or otherwise dispose of all or any portion of the
Securities in the absence of either an effective registration statement or an
exemption from the registration requirements of the Securities Act and
applicable state securities law;

                  3.4      Exempt Transaction. The Common Shares are being
offered and sold in reliance on specific exemptions from the registration
requirements of federal and state law and the Subscriber's representations,
warranties, agreements, acknowledgments and applicability of such exemptions and
the suitability of the Subscriber to acquire Common Shares.

                  3.5      Legends. It is understood that any certificates
evidencing the Common Shares shall bear the following legend:

                  "THE SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED
                  UNDER THE SECURITIES ACT OF 1933, AS AMENDED, OR APPLICABLE
                  STATE SECURITIES LAWS, NOR THE SECURITIES LAWS OF ANY OTHER
                  JURISDICTION. THEY MAY NOT BE SOLD OR TRANSFERRED IN THE
                  ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER THOSE
                  SECURITIES LAWS OR AN OPINION OF COUNSEL, REASONABLY
                  SATISFACTORY TO THE COMPANY, THAT THE SALE OR TRANSFER IS
                  PURSUANT TO AN EXEMPTION TO THE REGISTRATION REQUIREMENTS OF
                  THOSE SECURITIES LAWS."

         4.       Representations and Warranties of the Company. The Company
hereby makes the following representations and warranties to the Subscriber,
except as disclosed in the Disclosure Documents or otherwise disclosed to
Subscriber, which representations and warranties shall be true as of the date of
acceptance of this Agreement by the Company and as of Closing:

                  4.1      Organization, Good Standing, and Qualification. The
Company is a corporation duly organized, validly existing and in good standing
under the laws of the State of Texas and has all requisite corporate power and
authority to carry on its business as now conducted and as currently proposed to
be conducted. The Company is duly qualified to transact business and is in good
standing in each jurisdiction in which the failure to so qualify would have a
material adverse effect on the business or properties of the Company and its
subsidiaries taken as a whole. The Company is not the subject of any pending or,
to its knowledge, threatened or contemplated investigation or administrative or
legal proceeding by the Internal Revenue

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Service, the taxing authorities of any state or local jurisdiction, or the
Securities and Exchange Commission, or any state securities commission, or any
other governmental entity, which are required to be disclosed in the Disclosure
Documents and have not been disclosed.

                  4.2      Corporate Condition. The Company has timely filed all
forms, and reports and documents with the Securities and Exchange Commission
required to be filed by it under the Securities Exchange Act 1934, as amended
(the "Exchange Act") through the date hereof (collectively, the "SEC Reports").
Each of the SEC Reports, at the time filed, complied in all material respects
with the requirements of the Exchange Act. The Company has made available to the
Subscriber a copy of the Company's Form 10-KSB for the fiscal year ended
December 31, 1999, and a copy of the Company's Forms 10-QSB, 8-K and S-3 filed
by the Company since January 1, 2000 (the "Most Recent Filings Report"). Other
than as set forth in Schedule 4.2 attached hereto and made a part hereof, there
have been no material adverse changes in the Company's business, prospects,
operations or financial condition since the date of the Most Recent Filings
Report. The SEC Reports, together with Schedule 4.2 and any other documents
listed on Schedule 4.2(a) attached hereto and made a part hereof and furnished
herewith by the Company to the Subscriber are referred to collectively as the
"Disclosure Documents." The financial statements contained in the Disclosure
Documents have been prepared in accordance with generally accepted accounting
principles, consistently applied, and fairly present in all material respects
the consolidated financial condition of the Company as of the dates of the
balance sheets included therein and the consolidated results of its operations
and cash flows for the periods then ended. Without limiting the foregoing, there
are no material liabilities, contingent or actual that are not disclosed in the
Disclosure Documents (other than liabilities incurred by the Company in the
ordinary course of its business, consistent with its past practice, after the
periods covered by the Disclosure Documents). The Company has paid all material
taxes which are due, except for taxes which it reasonably disputes. There is no
material claim, litigation, or administrative proceeding pending, or, to the
best of the Company's knowledge, threatened or contemplated against the Company,
except as disclosed in the Disclosure Documents. This Agreement and the
Disclosure Documents do not contain any untrue statement of material fact and do
not omit to state any material fact required to be stated therein or herein
necessary to make the statements contained therein or herein not misleading in
the light of the circumstances under which they were made.

                  4.3      Authorization. All corporate action on the part of
the Company by its officers, directors and shareholders necessary for the
authorization, execution and delivery of this Agreement, the performance of all
obligations of the Company hereunder and the authorization, issuance and
delivery of the Common Shares have been taken, and this Agreement constitutes
valid and legally binding obligations of the Company, enforceable in accordance
with their terms; provided, however that enforceability is subject to: (i)
applicable bankruptcy, reorganization, insolvency, moratorium, fraudulent
conveyance, and similar federal and state laws affecting the rights and remedies
of creditors generally, and (ii) general principles of equity limiting the
availability of equitable remedies (including but not limited to the remedy of
specific performance), whether considered in a proceeding at law or in equity.
The Company has obtained all consents and approvals required for it to execute,
deliver and perform this Agreement.

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                  4.4      Valid Issuance of Common Shares. The Common Shares,
when issued, sold and delivered in accordance with the terms hereof, for the
consideration expressed herein, will be validly issued, fully paid and
nonassessable and, based in part upon the representations of the Subscriber in
this Agreement, will be issued in compliance with all applicable federal and
state securities laws. The Common Shares will be issued free of any preemptive
rights.

                  4.5      Compliance with Other Instruments. The Company is not
in violation or default of any provisions of its Restated Articles of
Incorporation or Bylaws as amended and in effect on and as of the date of this
Agreement or of any material provision of any material instrument or contract to
which it is a party or by which it is bound or, to its knowledge, of any
provision of any federal or state judgment, writ, decree, order, statute, rule
or governmental regulation applicable to the Company, which would have a
material adverse effect on the Company's business or prospects, except as
described in the Disclosure Documents. The execution, delivery and performance
of this Agreement and the consummation of the transactions contemplated hereby
will not result in any such violation or be in conflict with or constitute, with
or without the passage of time and giving of notice, either a default under any
such provision, instrument or contract or an event which results in the creation
of any lien, charge or encumbrance upon any assets of the Company.

                  4.6      Reporting Company. The Company is subject to the
reporting requirements of the Exchange Act, and has a class of securities
registered under Section 12 or Section 15 of the Exchange Act. When requested by
the Subscriber, the Company shall furnish copies of reports filed by the Company
with the Securities and Exchange Commission.

                  4.7      Authorized and Issued Shares. The authorized and
issued shares of the Company preferred stock, Common Stock and warrants,
options, and instruments convertible into Common Stock as of _______________ are
as set forth on Exhibit A.

                  4.8      Use of Proceeds. As of the date hereof, the Company
expects to use the proceeds from the Offering (less fees and expenses) for the
purposes set forth on Exhibit B hereto. These purposes are estimates and are
subject to change, but represent the Company's good faith best estimate of
anticipated uses.

                  4.9      Compliance with Laws. As of the date hereof, the
conduct of the business of the Company complies in all material respects with
all material statutes, laws, regulations, ordinances, rules, judgments, orders
or decrees applicable thereto. The Company has not received notice of any
alleged violation of any statute, law, regulations, ordinance, rule, judgment,
order or decree from any governmental authority. The Company shall comply with
all applicable securities laws with respect to the Offering.

                  4.10     No Rights of Participation. No person or entity,
including, but not limited to, current or former shareholders of the Company,
underwriters, brokers, agents or other third parties, has any right of first
refusal, preemptive right, right of participation, or any similar right to
participate in the Offering which has not been waived.

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                  4.11     Disclosures. There is no fact known to the Company
(other than general economic conditions known to the public generally) that has
not been disclosed in the Disclosure Documents that (a) could reasonably be
expected to have a material adverse effect on the business, financial condition
or results of operations of the Company, or which could reasonably be expected
to materially and adversely affect the properties or assets of the Company or
(b) could reasonably be expected to materially and adversely affect the ability
of the Company to perform its obligations pursuant to this Agreement and the
issuance of the Securities.

                  4.12     Representations True and Correct. The foregoing
representations, warranties and agreements are true, correct and complete in all
material respects, and shall survive the Closing and the issuance of the Common
Shares.

                  4.13     Termination Date of Offering. In no event shall the
Closing occur later than _____________, with any extension based upon an
agreement between the Company and the Subscriber.

                  4.14     Underwriter's Fees and Rights of First Refusal. The
Company is not obligated to pay any compensation or other fees, costs or related
expenditures in cash or securities to any underwriter, broker, agent or other
representative in connection with the Offering.

         5.       Covenants of the Company

                  5.1      Independent Auditors. The Company shall, until at
least two (2) years after the date of the Closing, maintain as its independent
auditors an accounting firm authorized to practice before the Securities and
Exchange Commission.

                  5.2      Corporate Existence and Taxes. The Company shall,
until at least two (2) years after the date of the Closing, maintain its
corporate existence in good standing (provided, however, that the foregoing
covenant shall not prevent the Company from entering into any merger or
corporate reorganization so long as the surviving entity in such transaction, if
not the Company, assumes all of the Company's obligations with respect to the
Securities) and shall pay all its taxes when due, except for taxes which the
Company disputes.

                  5.3      Filings with Securities and Exchange Commission. The
Company shall, upon request, provide the Subscriber with copies of its annual
reports on Form 10-KSB, quarterly reports on Form 10-QSB and current reports on
Form 8-K for as long as the Common Shares remain outstanding.

                  5.4      Listing. The Company shall use its best efforts to
maintain the listing of its Common Stock on the OTC Bulletin Board or a national
securities exchange or national quotation system.

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         6.       Miscellaneous

                  6.1      Representations and Warranties Survive the Closing;
Severability. The Subscriber's and the Company's representations and warranties
shall survive the Closing of the transaction provided for hereby notwithstanding
any due diligence investigation made by or on behalf of the party seeking to
rely thereon. In the event that any provision of this Agreement becomes or is
declared by a court of competent jurisdiction to be illegal, unenforceable or
void, this Agreement shall continue in full force and effect without said
provision.

                  6.2      Successors and Assigns. The terms and conditions of
this Agreement shall inure to the benefit of and be binding upon the respective
successors and assigns of the parties. Nothing in this Agreement, express or
implied, is intended to confer upon any party other than the parties hereto or
their respective successors and assigns any rights, remedies, obligations, or
liabilities under or by reason of this Agreement, except as expressly provided
in this Agreement. Neither party may assign its rights hereunder without the
prior written consent of the other parties.

                  6.3      Governing Law. This Agreement shall be governed by
and construed under the laws of the State of Texas without respect to conflict
of laws.

                  6.4      Execution in Counterparts Permitted. This Agreement
may be executed in any number of counterparts, each of which shall be
enforceable against the parties actually executing such counterparts, and all of
which together shall constitute one (1) instrument.

                  6.5      Titles and Subtitles; Gender. The titles and
subtitles used in this Agreement are used for convenience only and are not to be
considered in construing or interpreting this Agreement. The use in this
Agreement of a masculine, feminine or neither pronoun shall be deemed to include
a reference to the others.

                  6.6      Written Notices, Etc. Any notice, demand or request
required or permitted to be given by the Company or the Subscriber pursuant to
the terms of this Agreement shall be in writing and shall be deemed given when
delivered personally, or by facsimile (with a hard copy to follow by overnight
or two (2) day courier), addressed to the parties at the addresses and/or
facsimile telephone number of the parties set forth at the end of this Agreement
or such other address as a party may request by notifying the other in writing.

                  6.7      Expenses. Each of the Company and the Subscriber
shall pay all costs and expenses that it respectively incurs, with respect to
the negotiation, execution, delivery and performance of this Agreement.

                  6.8      Entire Agreement; Written Amendments Required. This
Agreement, the Common Stock certificates and the other documents delivered
pursuant hereto constitute the full and entire understanding and agreement
between the parties with regard to the subjects hereof and thereof, and no party
shall be liable or bound to any other party in any manner by any warranties,
representations or covenants except as specifically set forth herein. Neither
this

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Agreement nor any terms hereof may be amended, waived, discharged or terminated
other than by a written instrument signed by the party against whom enforcement
of any such amendment, waiver, discharge or termination is sought.

         7.       Subscription and Wiring Instructions; Irrevocability.

                  7.1      Subscription

                           (a)      Wire transfer of Subscription Funds.
                                    Subscriber shall send its subscription funds
                                    by wire transfer to the Company as follows:

                                    Bank:            Chase Bank Texas
                                    Account Name:    SI Diamond Technology, Inc.
                                    Account No.:     081-00053751
                                    ABA Routing No.: 113000609

                           (b)      Irrevocable Subscription. The Subscriber
                                    hereby acknowledges and agrees, subject to
                                    the provisions of any applicable laws
                                    providing for the refund of subscription
                                    amounts submitted by the Subscriber, that
                                    this Agreement is irrevocable and that the
                                    Subscriber is not entitled to cancel,
                                    terminate or revoke this Agreement;
                                    provided, however, that if the conditions to
                                    Closing are not satisfied or if the
                                    Disclosure Documents are discovered prior to
                                    Closing to contain statements which are
                                    materially inaccurate, or omit statements of
                                    material facts, the Subscriber may revoke or
                                    cancel this Agreement.

                           (c)      Company's Right to Reject Subscription. This
                                    Agreement shall be accepted by the Company
                                    when the Company countersigns this
                                    Agreement. The Subscriber hereby confirms
                                    that the Company has full right in its sole
                                    discretion to accept or reject the
                                    subscription of the Subscriber, in whole or
                                    in part, provided that, if the Company
                                    decides to reject such subscription, the
                                    Company must do so promptly and in writing.
                                    In the case of rejection, the Company will
                                    promptly return any rejected payments and
                                    (if rejected in whole) copies of all
                                    executed subscription documents (including
                                    without limitation this Agreement) to
                                    Subscriber.

                  7.2      Acceptance of Subscription. In the case of acceptance
of this subscription, ownership of the number of securities being purchased
hereby will pass to the Subscriber upon the Closing.

                  7.3      Subscriber to Forward Original Signed Subscription
Agreement to Company. The Subscriber agrees to courier to the Company its
original inked signed

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Subscription Agreement within three (3) days after faxing said signed Agreement
to the Company.

         8.       Number of Shares and Purchase Price. The undersigned
Subscriber hereby subscribes for and agrees to purchase _______ shares of Common
Stock for a total purchase price (to be paid by wire transfer) in the amount of
________________ dollars($____________) (the "Purchase Price").

         9.       Accredited Investor. The Subscriber is (please check
applicable box):

                  (a)      [ ]      a corporation,  business  trust, or
                                    partnership not formed for the specific
                                    purpose of acquiring the securities offered,
                                    with total assets in excess of $5,000,000.

                  (b)      [ ]      any trust, with total assets in excess
                                    of $5,000,000, not formed for the specific
                                    purpose of acquiring the securities offered,
                                    whose purchase is directed by a
                                    sophisticated person who has such knowledge
                                    and experience in financial and business
                                    matters that he is capable of evaluating the
                                    merits and risks of the prospective
                                    investment.

                  (c)      [x]      an individual, who

                           [ ]      is a director, executive officer or
                                    general partner of the issuer of the
                                    securities being offered or sold or a
                                    director, executive officer or general
                                    partner of a general partner of that issuer.

                           [ ]      has an individual net worth, or joint net
                                    worth with that person's spouse, at the time
                                    of the purchase exceeding $1,000,000.

                           [ ]      had an individual income in excess of
                                    $200,000 in each of the two most recent
                                    years or joint income with that person's
                                    spouse in excess of $300,000 in each of
                                    those years and has a reasonable expectation
                                    of reaching the same income level in the
                                    current year.

                  (d)      [ ]      an entity, each owner of which is an entity
                                    described in (a) or (b) above or is an
                                    individual described in (c) above.

         The undersigned acknowledges that this Agreement and the subscription
represented hereby shall not be effective unless accepted by the Company as
indicated below.

            (The remainder of this page is intentionally left blank.)

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         IN WITNESS WHEREOF, the undersigned Subscriber does hereby execute this
Agreement this _____ day of ________, 2001.

SUBSCRIBER

-------------------------
Name:

                                        DELIVERY INSTRUCTIONS:
                                        Please type or print address where your
                                        security is to be delivered

                                        ------------------------------------

                                        ------------------------------------

                                        ------------------------------------

ACCEPTANCE BY COMPANY:

         THIS SUBSCRIPTION IS ACCEPTED BY THE COMPANY AND THE COMPANY AGREES TO
BE BOUND BY THE TERMS AND CONDITIONS THEREOF THIS __ DAY OF ___________, 2001.

                                            By:
                                               --------------------------------
                                            Name: Douglas P. Baker
                                            Title:Vice President and Secretary

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                                   EXHIBIT "A"

                                 CAPITALIZATION

Shares of Common Stock Outstanding:

Series G Preferred Stock Outstanding:

Common Stock Options Outstanding:

Common Stock Warrants Outstanding:

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                                   EXHIBIT "B"

                                 USE OF PROCEEDS

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                                  SCHEDULE 1.2

                            MATERIAL ADVERSE CHANGES

                                       15<PAGE>   1

                                                            EXHIBIT 4.9

                          REGISTRATION RIGHTS AGREEMENT

         THIS REGISTRATION RIGHTS AGREEMENT ("Agreement") is entered into as of
________ ___, 2001, by and between SI DIAMOND TECHNOLOGY, INC., a Texas
corporation (the "Company") and the subscriber (hereinafter referred to as
"Subscriber" or "Investor") to the Company's offering ("Offering") of its Common
Stock pursuant to the Regulation D Subscription Agreements between the Company
and the Subscriber (the "Subscription Agreements") executed as of _______ ___,
2001.

         1.       DEFINITIONS. For purposes of this Agreement:

                  (a)      The terms "register", "registered," and
"registration" refer to a registration effected by preparing and filing a
registration statement or similar document with the Securities and Exchange
Commission (the "SEC") in compliance with the Securities Act of 1933, as amended
(the "Act") and pursuant to Rule 415 under the Act or any successor rule, and
the declaration or ordering of effectiveness of such registration statement or
document;

                  (b)      The term "Registrable Securities" means the shares of
the Company's Common Stock, together with any capital stock issued in
replacement of, in exchange for or otherwise in respect of such Common Stock
(the "Common Stock"), issued to Subscriber in the offering as identified in the
Subscription Agreements);

                  (c)      The term "Holder" means any person owning or having
the right to acquire Registrable Securities or any permitted assignee thereof;

                  (d)      The terms "Offering" and "Closing" shall have the
meanings ascribed to them in the Subscription Agreements.

         2.       VOLUNTARY REGISTRATION.

                  (a)      Notwithstanding any other obligation as identified in
this Agreement, the Company shall use its reasonable best efforts to voluntarily
register all of the Registrable Securities received by the Holder pursuant to
the Subscription Agreements (the "Holder's Shares") under the Act and any state
acts within ninety (90) days from the date of this Agreement (the
"Post-Effective Amendment Registration Period") by filing an amendment to the
Company's Registration Statement on Form S-3 previously filed with the SEC
November 17, 2000 (the "Registration Statement").

                  (b)      The Holder whose Holder's Shares are to be included
in any registration statement or amended registration to be filed by the Company
with the SEC pursuant to the Act and this Agreement shall furnish the Company
with such appropriate information as the Company shall reasonably request in
writing concerning the Holder as is

<PAGE>   2

necessary for the Company to comply with the disclosure requirements of the Act,
and the rules and regulations promulgated thereunder. Following the effective
date of any such registration statement, the Company shall, upon the reasonable
request of the Holder, supply such number of prospectuses meeting the
requirements of the Act as shall be requested by such Holder to permit such
Holder to make a public offering of all the shares of such Holder included
therein. The Company shall exercise good faith efforts to qualify the Holder's
Shares for sale in such states as the Holder shall reasonably designate.

         3.       OBLIGATIONS TO INCREASE THE NUMBER OF AVAILABLE SHARES. In the
event that the number of shares available under the amendment to the
Registration Statement to be filed pursuant to Section 2 above is insufficient
to cover all of the Holder's Registrable Securities then outstanding, then:

                  (a)      If the Company's efforts pursuant to the foregoing
Section 2(a) result in less than seventy-five percent (75%) of the Holder's
Shares being registered under the Act, then and in that event, the Company shall
use it's best reasonable efforts to file a new registration statement so as to
cover all of the Holder's Shares then outstanding. The Company shall file such
amendment or new registration within sixty (60) days of the date that the
Post-Effective Amendment Registration Period under Section 2 expires; or

                  (b)      If the Company's efforts pursuant to the foregoing
clause (a) result in seventy-five percent (75%) or more of the Holder's Shares
being registered under the Act, then and in that event, if the Company at any
time thereafter elects, or proposes, to register any of its authorized capital
stock under the Act with the SEC pursuant to which shares of the Company's
Common Stock owned by any shareholder of the Company may be registered, the
Company shall give prompt written notice (the "Registration Notice") to the
Holder of its intentions to register the Common Stock. Within fifteen (15) days
after the Registration Notice shall have been given to the Holder, the Holder
shall give written notice to the Company (the "Holder's Notice") stating the
number of Registrable Shares the Holder desires the Company to register (the
Holder's Shares"). The Company shall use its best efforts to register the
Holder's Shares under the Act and any state acts.

                  (c)      Anything contained herein to the contrary
notwithstanding, the Company has the right to withdraw and discontinue
registration of the Holder's Shares at any time prior to the effective date of
any such registration statement if the registration of the Holder's Shares is
withdrawn or discontinued.

         4.       OBLIGATIONS OF THE COMPANY. Whenever required under this
Agreement to effect the registration of any Registrable Securities, the Company
shall, as expeditiously as reasonably possible:

                  (a)      Prepare and file with the SEC a registration
statement with respect to such Registrable Securities and use its best efforts
to cause such registration statement to become effective.

                                       2

<PAGE>   3

                  (b)      Prepare and file with the SEC such amendments and
supplements to such registration statement and the prospectus used in connection
with such registration statement as may be necessary to comply with the
provisions of the Act with respect to the disposition of all securities covered
by such registration statement.

                  (c)      With respect to any registration statement filed
pursuant to this Agreement, keep such registration statement effective until the
earlier of (i) the date upon which the Holders of Registrable Securities covered
by such registration statement shall have sold such Registrable Securities; or
(ii) one (1) year after the date of the Closing of the Offering.

                  (d)      Furnish to the Holders such numbers of copies of a
prospectus, including a preliminary prospectus, in conformity with the
requirements of the Act, and such other documents as they may reasonably request
in order to facilitate the disposition of Registrable Securities owned by them.

                  (e)      Use its best efforts to register and qualify the
securities covered by such registration statement under such other securities or
Blue Sky laws of such jurisdictions as shall be reasonably requested by the
Holders of the Registrable Securities covered by such registration statement,
provided that the Company shall not be required in connection therewith or as a
condition thereto to qualify to do business or to file a general consent to
service of process in any such states or jurisdictions.

                  (f)      As promptly as practicable after becoming aware of
such event, notify each Holder of the happening of any event of which the
Company has knowledge, as a result of which the prospectus included in the
Registration Statement, as then in effect, includes an untrue statement of a
material fact or omits to state a material fact required to be stated therein or
necessary to make the statements therein, in light of the circumstances under
which they were made, not misleading, and use its best efforts promptly to
prepare a supplement or amendment to the Registration Statement to correct such
untrue statement or omission, and deliver a number of copies of such supplement
or amendment to each Investor as such Investor may reasonably request.

                  (g)      Provide Holders with written notice of the date that
a registration statement registering the resale of the Registrable Securities is
declared effective by the SEC.

                  (h)      Provide Holders and their representatives the
opportunity to conduct a reasonable due diligence inquiry of Company's pertinent
financial and other records and make available its officers, directors and
employees for questions regarding such information as it relates to information
contained in the registration statement, subject to all information received by
the Holders and their representatives being kept confidential.

                                       3
<PAGE>   4

         5.       FURNISH INFORMATION. It shall be a condition precedent to the
obligations of the Company to take any action pursuant to this Agreement with
regard to each selling Holder that such selling Holders shall furnish to the
Company such information regarding themselves, the Registrable Securities held
by them, and the intended method of disposition of such securities as shall be
required to effect the registration of their Registrable Securities or to
determine that registration is not required pursuant to Rule 144 or other
applicable provision of the Act.

         6.       EXPENSES OF REGISTRATION. All expenses, other than
underwriting discounts and commissions and fees and expenses of counsel to the
selling Holders, incurred in connection with the registrations pursuant to
Section 2, including (without limitation) all registration, filing and
qualification fees, printers' and accounting fees, fees and disbursements of
counsel for the Company, shall be borne by the Company.

         7.       INDEMNIFICATION. In the event any Registrable Securities are
included in a registration statement under this Agreement:

                  (a)      To the extent permitted by law, the Company will
indemnify and hold harmless each Holder, the officers and directors of each
Holder, any underwriter (as defined in the Act) for such Holder and each person,
if any, who controls such Holder or underwriter within the meaning of the Act or
the Securities Exchange Act of 1934, as amended (the "1934 Act"), against any
losses, claims, damages, or liabilities (joint or several) to which they may
become subject under the Act, the 1934 Act or other federal or state law,
insofar as such losses, claims, damages, or liabilities (or actions in respect
thereof) arise out of or are based upon any of the following statements,
omissions or violations (collectively a "Violation"): (i) any untrue statement
or alleged untrue statement of a material fact contained in such registration
statement, including any preliminary prospectus or final prospectus contained
therein or any amendments or supplements thereto, (ii) the omission or alleged
omission to state therein a material fact required to be stated therein, or
necessary to make the statements therein not misleading, or (iii) any violation
by the Company of the Act, the 1934 Act, any state securities law or any rule or
regulation promulgated under the Act, the 1934 Act or any state securities law;
and the Company will reimburse each such Holder, officer or director,
underwriter or controlling person for any legal or other expenses reasonably
incurred by them in connection with investigating or defending any such loss,
claim, damage, liability, or action; provided, however, that the indemnity
agreement contained in this subsection 7(a) shall not apply to amounts paid in
settlement of any such loss, claim, damage, liability, or action if such
settlement is effected without the consent of the Company (which consent shall
not be unreasonably withheld), nor shall the Company be liable in any such case
for any such loss, claim, damage, liability, or action to the extent that it
arises out of or is based upon a Violation which occurs in reliance upon and in
conformity with written information furnished expressly for use in connection
with such registration by any such Holder, officer, director, underwriter or
controlling person.

                                       4
<PAGE>   5

                  (b)      To the extent permitted by law, each selling Holder,
severally and not jointly, will indemnify and hold harmless the Company, each of
its directors, each of its officers who have signed the registration statement,
each person, if any, who controls the Company within the meaning of the Act, any
underwriter and any other Holder selling securities in such registration
statement or any of its directors or officers or any person who controls such
Holder, against any losses, claims, damages, or liabilities (joint or several)
to which the Company or any such director, officer, controlling person, or
underwriter or controlling person, or other such Holder or director, officer or
controlling person may become subject, under the Act, the 1934 Act or other
federal or state law, insofar as such losses, claims, damages, or liabilities
(or actions in respect thereto) arise out of or are based upon any Violation, in
each case to the extent (and only to the extent) that such Violation occurs in
reliance upon and in conformity with written information furnished by such
Holder expressly for use in connection with such registration; and each such
Holder will reimburse any legal or other expenses reasonably incurred by the
Company and any such director, officer, controlling person, underwriter or
controlling person, other Holder, officer, director, or controlling person in
connection with investigating or defending any such loss, claim, damage,
liability, or action; provided, however, that the indemnity agreement contained
in this subsection 7(b) shall not apply to amounts paid in settlement of any
such loss, claim, damage, liability or action if such settlement is effected
without the consent of the Holder, which consent shall not be unreasonably
withheld; provided, that, in no event shall any indemnity under this subsection
7(b) exceed the net purchase price of securities sold by such Holder under the
registration statement.

                  (c)      Promptly after receipt by an indemnified party under
this Section 7 of notice of the commencement of any action (including any
governmental action), such indemnified party will, if a claim in respect thereof
is to be made against any indemnifying party under this Section 7, deliver to
the indemnifying party a written notice of the commencement thereof and the
indemnifying party shall have the right to participate in, and, to the extent
the indemnifying party so desires, jointly with any other indemnifying party
similarly noticed, to assume the defense thereof with counsel mutually
satisfactory to the parties; provided, however, that an indemnified party shall
have the right to retain its own counsel, with the reasonably incurred fees and
expenses of one such counsel to be paid by the indemnifying party, if
representation of such indemnified party by the counsel retained by the
indemnifying party would be inappropriate due to actual or potential conflicting
interests between such indemnified party and any other party represented by such
counsel in such proceeding. The failure to deliver written notice to the
indemnifying party within a reasonable time of the commencement of any such
action, if prejudicial to its ability to defend such action, shall relieve such
indemnifying party of any liability to the indemnified party under this Section
7, but the omission so to deliver written notice to the indemnifying party will
not relieve it of any liability that it may have to any indemnified party
otherwise than under this Section 7.

                  (d)      In the event that the indemnity provided in paragraph
(a) or (b) of this Section 7 is unavailable to or insufficient to hold harmless
an indemnified party for any

                                       5
<PAGE>   6

reason, the Company and each Holder of Registrable Securities agree to
contribute to the aggregate claims, losses, damages and liabilities (including
legal or other expenses reasonably incurred in connection with investigating or
defending same) (collectively "Losses") to which the Company and one or more of
the Holders of Registrable Securities may be subject in such proportion as is
appropriate to reflect the relative fault of the Company and the Holders in
connection with the statements or omissions which resulted in such Losses;
provided, however, that in no case shall any Holder be responsible for any
amount in excess of the net purchase price of securities sold by it under the
registration statement. Relative fault shall be determined by reference to
whether any alleged untrue statement or omission relates to information provided
by the Company or by the Holders. The Company and the Holders agree that it
would not be just and equitable if contribution were determined by pro rata
allocation or any other method of allocation which does not take account of the
equitable considerations referred to above. Notwithstanding the provisions of
this paragraph (d), no person guilty of fraudulent misrepresentation (within the
meaning of Section 11(f) of the Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation. For purposes of
this Section 7, each person who controls a holder of Registrable Securities
within the meaning of either the Act or the 1934 Act and each director, officer,
partner, employee and agent of a Holder shall have the same rights to
contribution as such holder, and each person who controls the Company within the
meaning of either the Act or the 1934 Act and each director of the Company, and
each officer of the Company who has signed the registration statement, shall
have the same rights to contribution as the Company, subject in each case to the
applicable terms and conditions of this paragraph (d).

                  (e)      The obligations of the Company and Holders under this
Section 7 shall survive the redemption and conversion, if any, of the Common
Stock, the completion of any offering of Registrable Securities in a
registration statement under this Agreement, and otherwise.

         8.       REPORTS UNDER SECURITIES EXCHANGE ACT OF 1934. With a view to
making available to the Holders the benefits of Rule 144 promulgated under the
Act and any other rule or regulation of the SEC that may at any time permit a
Holder to sell securities of the Company to the public without registration, the
Company agrees to:

                  (a)      make and keep public information available, as those
terms are understood and defined in SEC Rule 144;

                  (b)      file with the SEC in a timely manner all reports and
other documents required of the Company under the Act and the 1934 Act; and

                  (c)      furnish to any Holder, so long as the Holder owns any
Registrable Securities, forthwith upon request (i) a written statement by the
Company, if true, that it has complied with the reporting requirements of SEC
Rule 144, the Act and the 1934 Act, (ii) a copy of the most recent annual or
quarterly report of the Company and such other reports and

                                       6
<PAGE>   7

documents so filed by the Company, and (iii) such other information as may be
reasonably requested in availing any Holder of any rule or regulation of the SEC
which permits the selling of any such securities without registration.

         9.       NOTICES. All notices required or permitted under this
Agreement shall be made in writing signed by the party making the same, shall
specify the section under this Agreement pursuant to which it is given, and
shall be addressed if to (i) the Company at: 3006 Longhorn Boulevard, Suite 107,
Austin, Texas 78758, Telephone No. (512) 339-5020, Facsimile No. (512) 339 -
5021, and (ii) the Holders at their respective last address as the party shall
have furnished in writing as a new address to be entered on such register. Any
notice, except as otherwise provided in this Agreement, shall be made by fax and
shall be deemed given at the time of transmission of the facsimile.

         10.      TERMINATION. This Agreement shall terminate on the earlier to
occur of (a) the date that is one (1) year from the date of the Closing or (b)
the date the resale by Holders of all Registrable Securities described in any
registration statement filed pursuant to this Agreement is completed; but
without prejudice to (i) the parties' rights and obligations arising from
breaches of this Agreement occurring prior to such termination or (ii) other
indemnification obligations under this Agreement.

         11.      ASSIGNMENT. No assignment, transfer or delegation, whether by
operation of law or otherwise, of any rights or obligations under this Agreement
by the Company or any Holder, respectively, shall be made without the prior
written consent of the majority in interest of the Holders or the Company
respectively; provided that the rights of a Holder may be transferred to a
subsequent holder of the Holder's Registrable Securities (provided such
transferee shall provide to the Company, a writing executed by such transferee
agreeing to be bound as a Holder by the terms of this Agreement); and provided
further that the Company may transfer its rights and obligations under this
Agreement to a purchaser of all or a substantial portion of its business if the
obligations of the Company under this Agreement are assumed in connection with
such transfer, either by merger or other operation of law (which may include
without limitation a transaction whereby the Registrable Shares are converted
into securities of the successor in interest) or by specific assumption executed
by the transferee.

         12.      MISCELLANEOUS.

                  (a)      Governing Law. This Agreement shall be governed by
and construed in accordance with the laws of the State of Texas without giving
effect to conflict of laws.

                  (b)      Successors and Assigns. Except as otherwise provided
herein, the provisions hereof shall inure to the benefit of, and be binding
upon, the successors, assigns, heirs, executors and administrators of the
parties hereto.

                                       7
<PAGE>   8

                  (c)      Delays or Omissions. No delay or omission to exercise
any right, power or remedy accruing to any holder of any Registrable Shares,
upon any breach or default of the Company under this Agreement, shall impair any
such right, power or remedy of such holder nor shall it be construed to be a
waiver of any such breach or default, or an acquiescence therein, or of or in
any similar breach or default thereunder occurring, nor shall any waiver of any
single breach or default be deemed a waiver of any other breach or default
thereafter occurring. Any waiver, permit, consent or approval of any kind or
character on the part of any holder of any breach or default under this
Agreement, or any waiver on the part of any party of any provisions of
conditions of this Agreement, must be in writing and shall be effective only to
the extent specifically set forth in such writing. All remedies, either under
this Agreement, or by law or otherwise afforded to any holder, shall be
cumulative and not alternative.

                  (d)      Counterparts. This Agreement may be executed in any
number of counterparts, each of which may be executed by less than all of the
Investors, each of which shall be enforceable against the parties actually
executing such counterparts, and all of which together shall constitute one
instrument.

                  (e)      Severability. In the case any provision of this
Agreement shall be invalid, illegal or unenforceable, the validity, legality and
enforceability of the remaining provisions shall not in any way be affected or
impaired thereby.

            {The remainder of this page is intentionally left blank.}

                                       8
<PAGE>   9

         The foregoing Registration Rights Agreement is hereby executed as of
the date first above written.

                                            SI DIAMOND TECHNOLOGY, INC.

                                            By:
                                               ---------------------------------
                                            Name:   Douglas P. Baker
                                            Title:  Vice President and Secretary

                                     SUBSCRIBER(S)

                                           Subscriber's Name:

                                           By:
                                               ---------------------------------

                                           By:
                                               ---------------------------------

                                           Address:

                                       9

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