This article describes the synthesis and characterization of copolymers of methyl methacrylate (MMA) and N-4-chlorophenyl maleimide (PC)/N-3-chlorophenyl maleimide (MC). The copolymers were synthesized by varying the mole fraction of N-aryl maleimides from 0.1 to 0.5 in the initial feed using azobisisobutyronitrile (AIBN) as an initiator and tetrahydrofuran (THF) as the solvent. The copolymer composition was determined from the H-1-NMR spectra by taking the ratio of proton resonance signals due to methoxy protons (delta = 3.59 ppm) of MMA and aromatic protons (delta = 7.2-7.4 ppm) of N-aryl maleimides. The reactivity ratios for MMA-PC and MMA-MC copolymers were found to be 0.952 (r(1)), 0.029 (r(2)) and 0.833 (r(1)) and 0.033 (r(2)), respectively. Thermal characterization of the copolymers was done using differential scanning calorimetry (DSC) and dynamic thermogravimetry. Initial decomposition temperature and glass transition temperature increased with increasing mole fraction of N-aryl maleimide content in the copolymers.