Styrene (St)/Methyl methacrylate (MMA) block copolymers were obtained by using a two-step procedure. In the first step, St was polymerized using 4, 4′-azobis(4-cyanopentanoic acid) (ACPA) as initiator yielding polymers with carboxyl end groups. Subsequently, photoinduced polymerization of MMA initiated by carboxyl terminated polymers in conjunction with lead tetraacetate (Pb(OAc)4) provided formation of block copolymers.