Poly(p-phenylene sulfide) (PPS) was obtained by polymerization of 4-bromobenzenethiol in the presence of a free radical initiator, which can be any aryl disulfide, although bis(4-bromophenyl) disulfide (1) is recommended. The PPS polymer obtained has a weight average molecular weight of 19 600 (PD = 2.8), as determined by high-temperature GPC when 1.0 mol % of 1 is used as the initiator after 96 h of reaction. Its molecular weight and structural information have also been studied by thermal analyses, elemental analyses, and a FT-IR study. Other poly(thioarylene)s were prepared by copolymerization of arenedithiols and dibromo aromatic compounds in the presence of a catalytic amount of 1 as initiator. A mechanism for the polymerizations is proposed.