(805 ILCS 5/3.15) (from Ch. 32, par. 3.15)
    Sec. 3.15. Defense of Ultra Vires. No act of a corporation and no conveyance or transfer of real or personal property to or by a corporation shall be invalid by reason of the fact that the corporation was without capacity or power to do such act or to make or receive such conveyance or transfer, but such lack of capacity or power may be asserted:
    (a) In a proceeding by a shareholder against the corporation to enjoin the doing of any act or acts or the transfer of real or personal property by or to the corporation. If the unauthorized acts or transfer sought to be enjoined are being, or are to be, performed or made pursuant to any contract to which the corporation is a party, the court may, if all of the parties to the contract are parties to the proceeding and if it deems the same to be equitable, set aside and enjoin the performance of such contract, and in so doing shall allow to the corporation or the other parties, as the case may be, compensation for the loss or damage sustained by either of them which may result from the action of the court in setting aside and enjoining the performance of such contract, but anticipated profits to be derived from the performance of the contract shall not be awarded by the court as a loss or damage sustained.
    (b) In a proceeding by the corporation, whether acting directly or through a receiver, trustee, or other legal representative, or through shareholders in a representative suit, against the officers or directors of the corporation for exceeding their authority.
    (c) In a proceeding by the State, as provided in this Act, to dissolve the corporation, or in a proceeding by the State to enjoin the corporation from the transaction of unauthorized business.
(Source: P.A. 83-1025.)