Poly(piperazinenaminonitriles), analogs of poly(piperazinamides), were synthesized by interfacial polycondensation of piperazine or 2,5-dimethylpiperazine (cis or trans) with bis-electrophilic monomers (1,3- or 1,4-bis(1-chloro-2,2-dicyanovinyl)benzene). Because of the absence of hydrogen bonding, poly(piperazinenaminonitriles) showed limited solubility in dipolar aprotic solvents and, compared to poly(piperazinamides), gave lower molecular weight materials of lower thermal stability. The barrier to internal rotation of enaminonitrile groups, measured using dynamic NMR spectroscopy of model compounds, was comparable to the barrier to internal rotation measured for amide groups.