CdS nanocrystal-sensitized solar cells (NCSSCs) were investigated by using polyaniline (PANI) as a replacement for conventional platinum counter electrode. The growth time of the NCs significantly affects the solar cell performance. At an optimum growth, the NCSSCs exhibit 0.83% of the conversion efficiency in comparison to 0.13% for the identical cells without CdS NCs. Electrochemical impedance spectroscopy showed that the charge transfer in the solar cells with CdS nanocrystals was improved. The enhanced overall energy conversion efficiency by NCs is attributed to improved light absorption and suppressed recombination rate of interfacial charges with injection, resulting in significantly improved charge transfer and electron life time. In addition, the PANI electrodes with large surface area and ideal corrosion-inertness toward polysulfide redox exhibit promising application potential as a counter electrode for NCSSCs. This study demonstrates that the solution grown CdS nanocrystals and polyaniline are potentially useful for fabricating high performance NCSSCs, which is technically attractive for large scale and economic production.