Copolymerization of methylmethacrylate (MMA) with 1-vinyl-2-pyrrolidone (N-VP), initiated by p-nitrobenzyl triphenyl phosphonium ylide in dioxane at 60 C for 60 min under inert atmosphere of nitrogen yields alternating copolymer as evidenced by the values of r 1 ¼ 0.01 and r 2 ¼ 0.02. The kinetic expression was R p / [I] 0.75 [MMA] 1.2 [VP] 1.2 . The overall activation energy is 45.4 kJ/mol. The FTIR bands of OCH 3 of MMA at 1725 cm À1 and ÀC=O of N-VP at 1679 cm À1 , confirms the incorporation of both the monomers in the copolymer. The glass transition temperature of the copolymer is 133 C. The GPC data shows the polydispersity index at about 1.5. The ESR spectroscopy confirm phenyl radical responsible for initiation.