Novel trisubstituted ethylenes, phenoxy ring-substituted isopropyl phenylcyanoacrylates were prepared and copolymerized with styrene. The compositions of the copolymers were calculated from nitrogen analysis and the structures were analyzed by IR, H 1 and 13 C-NMR. The thermal gravimetric analysis indicated that the copolymers decompose in two steps, first in the 129-500C range with residue (2-10%wt), which then decomposed in the 500-800ºC range.