The effects of various polymerization times on the properties and conductivity of poly(methyl methacrylate)/polyaniline (PMMA/PANi) copolymer has been investigated. Different polymerization times, such as 1 h, 2 h, and 3 h, have been employed during free radical copolymerization of PMMA/PANi copolymer. The properties of newly synthesized PMMA/PANi copolymer were discussed with the help of Fourier transform infrared (FTIR), ¹H nuclear magnetic resonance (NMR) spectroscopies, UV-Vis spectroscopy, and transmission electron microscopy. All copolymers showed electrical conductivity of a semi-conductor material, compared with PMMA itself. It was found that the reaction played a significant role, especially at optimum polymerization time, where PANi formation and conductivity was at its highest. Our present work demonstrates that copolymer film could be a promising material to fabricate polymer conducting film in many electronics applications.