Polymeric-inorganic nanocomposite catalysts were synthesized by facile one-pot chemical polymerization of pyrrole in the presence of titanium dioxide nanoparticles. The electrical, optical, photovoltaic performance of dye sensitized solar cell(DSSC) and visible light driven photocatalytic activities of the nanocomposite were investigated. The prepared nanocomposite displays excellent photo-activity, attaining 100% degradation of methyl orange dye in 60 min under visible light source while 55% for pure TiO_2 under similar experimental conditions. The photovoltaic performance of the polypyrrole-titanium dioxide(PPy-TiO_2) nanocomposite has a 51.4% improvement with a photo-conversion efficiency of 8.07% as compared to pure TiO_2 based DSSC. By comparing the physical mixture of the PPy-TiO_2 nanocomposite and pristine TiO_2, the enhanced activity of the PPy-TiO_2 nanocomposite can be attributed to the reduced charge transfer resistance, outstanding electrical conductance of the PPy, the nano-sized structure of TiO_2 and their synergetic effect. Furthermore, the PPy-TiO_2 nanocomposite shows excellent electrical conductivity and isothermal stability under ambient conditions below 110?C. Polymeric-inorganic nanocomposite catalysts were synthesized by facile one-pot chemical polymerization of pyrrole in the presence of titanium dioxide nanoparticles. The electrical, optical, photovoltaic performance of dye sensitized solar cell (DSSC) and visible light driven photocatalytic activities of the nanocomposite were investigated . The prepared nanocomposite displays excellent photo-activity, attaining 100% degradation of methyl orange dye in 60 min under visible light source while 55% for pure TiO 2 under similar experimental conditions. The photovoltaic performance of the polypyrrole-titanium dioxide (PPy-TiO 2) nanocomposite has a 51.4% improvement with a photo-conversion efficiency of 8.07% as compared to pure TiO 2 based DSSC. By comparing the physical mixture of the PPy-TiO 2 nanocomposite and pristine TiO 2, the enhanced activity of the PPy-TiO 2 nanocomposite can be attributed to the reduced charge transfer resistance, outstanding electrical conductance of the PPy, the na no-sized structure of TiO 2 and their synergetic effect..., PPy-TiO 2 nanocomposite shows excellent electrical conductivity and isothermal stability under ambient conditions below 110 ° C.