Herein, we have reported a facile method to synthesize surface passivated carbon dots (CDs) with high quantum yield. The structure and optical properties of the CDs are successfully investigated using high-resolution transmission electron microscopy; dynamic light scattering; and UV-vis, fluorescence, and Fourier transform infrared spectroscopy (FTIR). The synthesized CDs with excellent water solubility have been utilized to prepare nanostructured polyaniline (PANT) where CDs act both as a dopant as well as nucleating agent. The synthesis of PANI is achieved through a simple and one pot chemical oxidative polymerization. The UV-vis and FTIR data clearly indicates the formation of highly doped PANI (emeraldine salt form), which will really be helpful for fabricating photovoltaic device. We have examined the current voltage characteristics of CD-PANI samples both in dark and illuminated state, which evidently designates the enhancement of current in the illuminated state. Hence, we have employed the CD-PANI samples for photovoltaic study, and the DSSCs are studied under illumination of 100 mW/cm(2). Among the CD-PANI samples, CDPA10 shows a maximum power conversion efficiency of 3.65%.