Free-radical copolymerization of 4-nitrophenyl methacrylate (NPMA) with styrene (STY) was carried out at 65 degrees C in 2-butanone by using benzoyl peroxide (BPO) as initiator. NPMA was characterized by spectral and microelemental analysis. Homo-and copolymers were characterized by IR, H-1-, and C-13-NMR studies and their copolymer compositions were evaluated by H-1-NMR spectroscopic technique. The copolymer reactivity ratios were calculated using Fineman-Ross, Kelen-Tudos, and extended Kelen-Tudos methods. The Q,e values for NPMA were determined by Alfrey-Price Q,e rule. Thermal properties of the homo- and copolymers were studied by thermogravimetric analysis and differential scanning calorimetry methods.