50 ILCS 445/7
Bonds issued under authority of this Act bearing signatures of persons who are officers of the authority on the date of issuance are valid and binding obligations even if at the time the bonds are delivered and paid for any of the persons whose signatures appear on the bonds have ceased to be officers of the authority. The validity of the bonds does not depend on nor is it affected by the validity or regularity of any proceedings relating to the acquisition, purchase, construction, rebuilding, improvement or extension of the industrial project for which the bonds are issued. The resolution authorizing the bonds may provide that the bonds contain a provision that they are issued under authority of this Act. Such a provision is conclusive evidence of the validity or regularity of the issuance of the bonds.
50 ILCS 445/7