Bis-electrophilic aromatic monomers were polymerized with hexamethylenediamine to high molecular weight polyenaminonitriles. All the polymers, except that containing a sulfone group, were soluble in polar, aprotic solvents and possessed film-forming properties. The polymers and their model compounds were characterized by spectroscopic methods. Some of the polymers possessed varying degrees of crystallinity as shown by differential scanning calorimetry. Thermogravimetry also revealed a surprising amount of thermal stability for macromolecules containing aliphatic segments.