A non-conjugated polymer poly (vinylmercaptobenzothiazole) (PVMBT) shows semi conducting properties in presence of electron acceptor-iodine. The enhancement of conductivity is presumably due to the formation of charge transfer (CT) complexes between iodine and the lone pair of the nitrogen atom of the polymer. This CT complex is characterized through FTIR, UV, ESR, electrical conductivity measurement and dependence of conductivity on temperature. The thermal properties of PVMBT have also been studied with the help of DSC and TGA.