Four new polyenaminonitriles, soluble in common organic solvents, are synthesized by condensation of bis(chlorovinyledene cyanide) monomers with two different aromatic diamines. Thermal stability of these heat-resistant polymers is discussed in terms of their structure-property relationships. Curing of polyenaminonitriles, which cure without evolution of small molecules, was studied by differential scanning calorimetry (DSC) and infrared spectroscopy.