In this research, copolymerization reaction of sulfonated dichlorobenzene and dichloro-terminated aromatic oligomer was investigated for the preparation of sulfonated copolymers as proton conductive membranes. We found that a versatile synthetic method without using costly Ni(0) catalyst, where NiBr2 could be reduced to Ni(0) with Zn in situ during the copolymerization reaction, was applicable. The resulting copolymer had comparable molecular weight and proton conductivity to those of the copolymers prepared by the previous method using Ni(0).