Maleimido derivative (MAF) of aniline-formaldehyde (AF) resin was prepared by the reaction of AF with maleic anhydride. The MAF was characterized by elemental analysis, IR spectroscopy and thermogravimetry. A MAF having 3 to 4 maleimido groups was reacted with various grades of furan resin (FR) through Diels-Alder reaction. The resultant polyimides were characterized by IR spectral studies and thermal properties. Both MAF and FR components were polymerized in situ on glass and carbon fiber. The physical, chemical and mechanical properties of the resultant composites have been determined.