This article reports a synthetic methodology for single step preparation of telechelic poly(disulfide)s (PDS) by step-growth polymerization between a di-thiol and a commercially available monomer 2,2-dithiodipyridine in presence of a functional group appended pyridyl disulfide moiety as the mono-functional impurity (MFI). Redox-destructible well-defined segmented PDSs with functional chain terminal, predicted and tunable degree of polymerization and narrow polydispersity index (<2.0) could be synthesized under a mild reaction condition. Using an appropriate MFI, PDS could be synthesized with trithiocarbonate chain terminals in a single step, which could be further used as macro chain-transfer agent (CTA) for chain growth polymerization under RAFT mechanism producing ABA type tri-block copolymer wherein the B block consists of the degradable PDS chain. By copolymerization between a hydrophobic di-thiol monomer and a hydroxyl group appended di-thiol monomer, PDS could be prepared with pendant hydroxyl functional group which was utilized to initiate ring opening polymerization of cyclic lactide monomers producing well-defined degradable graft-copolymer. The pendant hydroxyl groups were further utilized to anchor a polar carboxylic group to the degradable PDS backbone which under basic condition showed aqueous self-assembly generating micelle-like structure with hydrophobic guest encapsulation ability and glutathione responsive sustained release. (c) 2017 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 194-202