Poly(N,N-diacylhydrazone)s, which contain imide and imine functions linked by nitrogen-nitrogen bonds, were synthesized from terephthalaldehyde dihydrazone and aromatic and aliphatic dianhydrides. One of the aromatic polymers was also prepared from N,N'-diamino-l,4,5,8-naphthalenetetracarboxylic diimide and terephthaldehyde. The polymers exhibited moderate thermal stability and were shown to degrade initially by cleavage of nitrogen-nitrogen bonds.