Homopolymerizations and copolymerizations of N-phenyl itaconimide (PhII), N-(4-chlorophenyl) itaconimide (ClPhII), N-(4-methylphenyl) itaconimide (MPhII), and N-1-naphthyl itaconimide (NII) were carried out at 60℃ by using azobisisobutyronitrile (AIBN) as an initiator in tetrahydrofuran. The initial rates of the polymerization were R_p=k[AIBN]^<0.6>[PhII]^<1.5>, R_p=k[AIBN]^<0.5>[ClPhII]^<1.1>, R_p=k[AIBN]^<0.5>[MPhII]^<1.0>, and R_p=k[AIBN]^<0.5>[NII]^<1.0>, where k is rate constant. The over-all activation energies (E) and frequency factors (A) were E=19.5 kcal/mol (PhII), 16.1 kcal/mol (ClPhII), 20.1 kcal/mol (MPhII), 17.5 kcal/mol (NII) and A=9.9×10^9 (PhII), 3.1×10^7 (ClPhII), 1.7×10^<10> (MPhII), 4.5×10^8 (NII). The reactivity ratios were determined as r_1=0.08, r_2=0.05