Electrophilic trisubstituted ethylene monomers, ring-substituted methyl 2-cyano-3-phenyl-2-propenoates, RC6H4CH = C(CNC02CH, (where R is 0-C1, m-C1, p-C1, p-Br, and p-F) were prepared and copolymerized in solution with styrene at equimolar monomer feed composition in the presence of a radical initiator, AIBN at 80°C. The order of reactivity (lh,) for the trisubstituted ethylene monomers was p-C1 (3.0) > m-CI (2.9) > p-Br (2.3) > 0-C1 (2.0) > p-F (1.4). High Tg's of the copolymers in comparison with that of polystyrene indicates substantial decrease in chain mobility of the copolymer due to high dipolar character of the trisubstituted monomer units.