The novel random linear copolythioester Polydecylthiodipropionate-co-decyldodecanedioate (PDTDD), a class of biopolymer including sulfur in the form of a thioester in the polymer backbone was synthesised by mixing 3,3’thiodipropionic acid, dodecanedioic acid and 1,10 decanediol monomers with titanium tetra isopropoxide catalyst using direct melt polycondensation method. The different physical properties of copolyester such as inherent viscosity by Ubbelohde viscometer, solubility test by various solvents, Tg by Differential Scanning Colorimetry (DSC) and crystalline nature by X-ray diffraction (XRD) technique was determined and studied in detail. The chemical structure of the copolyester was investigated by FTIR, 1H-NMR and 13C-NMR spectroscopy. The synthesized compounds were tested for human pathogenic bacteria using well diffusion method, in vitro cytotoxicity against normal (Vero cell line) and cancer (A549 lung cancer cell line) by MTT assay. Also in vitro antioxidant property of copolymer was studied.