Modification of the oligo(phenylene sulfide) chain at the ends with reactive groups such as chloro, bromo, iodo, and carboxyl to enhance its reactivtiy was performed. alpha,omega-Dihalooligo(p-phenylene sulfide) was synthesized through the oxidative polymerization of diphenyl disulfide in the presence of bis(4-halophenyl)disulfide. Linear oligo(p-phenylene sulfide) (OPS) terminated by Cl or Br with a high degree of functionality was obtained by a one-pot process. alpha-Carboxy-OPS was synthesized by the thermolysis of the disulfide-bond of the OPS in the presence of an aromatic iodide having a carboxyl group. The carboxy-terminated OPS was used for the synthesis of polyamide-graft-OPS copolymers.