Unsaturated cyano-substituted polyamide and polyimides were prepared from the reactions of diaminomaleonitrile with terephthaloyl dichloride and tetracarboxylic dianhydrides such as pyromellitic dianhydride and benzophenone tetracarboxylic dianhydride. The polymers were characterized by inherent viscosity measurements, by FTIR and H-1-NMR spectroscopy, as well as by DTA and TGA. They were soluble in polar aprotic solvents and certain strong inorganic and organic acids. Upon curing at 300-degrees-C for 70 h, cross-linked polymers were obtained that were stable up to 397-426-degrees-C in N2 or air and afforded anaerobic char yield of 56-61% at 800-degrees-C. Their glass transition temperatures as determined by the thermal mechanical analysis (TMA) method were 210-249-degrees-C.