The structure of VAC-HECP copolymers was characterized by IR and NMR spectroscopy. A comparison of the spectra of the monomers, copolymers, and polyvinyl acetate with the spectra of ring-unsubstituted ethyl 2-cyano-3-phenyl-2-propenoate -VAC shows, that the reaction between the HECP monomers and VAC is a copolymerization. . Relatively high Tg of the copolymers (95-115 ºC) in comparison with that of polyvinyl acetate, Tg = 28-31ºC indicates decrease of chain mobility of the copolymer due to the high dipolar character of the HECP structural units. Information on the degradation of the copolymers was obtained from thermogravimetric analysis. Decomposition of the copolymers in nitrogen occurred in two steps, apparently due to acetic acid elimination in 160-340ºC range followed by more slow decomposition of formed residue (15.1-1.5 wt%), which then decomposed in the 500-650ºC range.