The development of new nanomaterials with multifunctional properties that can be utilized for solar harvesting and gas sensing with improved light absorption, improved charge transport performance, enhanced gas sensitivity and selectivity indicates one of the leading scientific challenges driven by enormous energy demands and emission of toxic gases in industrial processes, ensuing hazards in public health, industries and national security. Thus, herein, we focus on the synthesis of TiO2 doped with transitional (Cu) and noble metals (Ag and Au) and their incorporation in P3HT polymer matrix for inorganic-organic photovoltaic solar cells and low operating temperature chemiresistive sensors. The presence and the role of the metallic dopants in the hybrid nanostructure (P3HT:TiO2-Ag, P3HT:TiO2-Au, P3HT:TiO2-Cu, P3HT:TiO2-Cu-Ag and P3HT:TiO2-Ag-Au) was characterized in detail using X-ray diffraction (see Figure 1), scanning electron microscopy-energy dispersive X-ray study and transmission electron microscopy analyses. The surface plasmonic resonance behaviour and charge transfer, owing to the delocalization of photoexcited electrons from the conduction domain of polymer to the domain of metallic dopant was probed using electron spin resonance, ultra-violet visible absorption, photoluminescence and x-ray photoelectron spectroscopy measurements. The role of transitional and noble metals on the improved gas selectivity, sensitivity, response-recovery times, limit of detection and long-term stability were also investigated towards various target gases at low operating temperatures.