Methacrylate based monomer, 4-chloronaphthyl methacrylate (4-CNMA) was synthesized by reacting 4-chloro naphthol with methacryloyl chloride in the presence of triethylamine (NR3) at 0-5C. The free-radical initiated copolymerization of (4-CNMA), with acrylonitrile (AN) was carried out in 1,4-dioxane-dimethyl sulfoxide mixture (8:2) solution at 70 1C using 2,2'-azobisisobutyronitrile (AIBN) as an initiator with different monomer-to-monomer ratios in the feed. The monomer 4-CNMA, poly(4-CNMA) and copolymers were characterized by FT-IR and 1H-and 13C-NMR spectral studies. The copolymer composition obtained by elemental analysis led to the determination of reactivity ratios employing Fineman-Ross (F-R), Kelen-Tudos (KT) and Extended Kelen-Tudos (EKT) linearization methods. These parameters were also estimated using a non-linear computational fitting procedure, known as reactivity ratios error in variable model (RREVM). The solubility of the polymers was tested in various polar and non-polar solvents. Gel permeation chromatography was employed to determine the molecular weights (Mw and Mn) and polydispersity index of polymers. Thermogravimetric analysis of the polymers reveals that the thermal stability of the copolymers increases with increase in the mole fraction of 4-CNMA in the copolymers. The prepared homo and copolymers were tested for their antimicrobial activity against bacteria, fungi and yeast.