Novel trisubstituted ethylenes, chlorophenoxy ring-substituted isopropyl 2-cyano-3-phenyl-2-propenoates, RPhCH=C(CN)CO₂CH(CH₃)₂(where R is 2-(4-chlorophenoxy), 3-(4-chlorophenoxy), 4-(3-chlorophenoxy), 4-(4-chlorophenoxy), 3-(3,4-dichlorophenoxy), 3-(3,5-dichlorophenoxy), 4-(2,4-dichlorophenoxy) were prepared and copolymerized with styrene. The ethylenes were synthesized by the piperidine catalyzed Knoevenagel condensation of ring-substituted benzaldehydes and isopropyl cyanoacetate, and characterized by CHN analysis, FTIR, ¹H and ¹³C-NMR. All the ethylenes were copolymerized with styrene in solution with radical initiation (ABCN) at 70°C. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by FTIR, ¹H and ¹³C NMR. Decomposition of the copolymers in nitrogen occurred in two steps, first in the 250-500ºC range with residue (4.9-9.8% wt), which then decomposed in the 500-800ºC range.