Аннотация:Reaction modeling copolymerization of bis(cyanate) of 4,4'-isopropylidenediphenol and bis(maleimide) was studied using the interaction of N-phenyl cyanate with N-phenylmaleimide as an example. it was shown that the starting reagents are involved into a complex step-by-step reaction yielding a cyclochain polymer and a set of polycyclochain oligomers with a variable molecular mass and composition. It is possible that graft interpenetrating networks are formed under the real conditions of polymer synthesis.