A novel method was used to synthesize CdS single-crystal nanorods directly in the presence of conjugated polymer poly(3-hexylthiophene-2,5-diyl) (P3FIT), where the P3HT is acting as a molecular template for geometrical manipulation of CdS nanocrystals and, in the meantime, as in efficient charge conductor in composite form. Such a templating process allows the CdS nanorods with various aspect ratios to be easily manufactured via a controlled solvency of a cosolvent Mixture, under which the conformational variation of the P3HT chain can be manipulated. The mechanism of in situ growth of high-aspect-ratio CdS nanorod is proposed based on spectroscopic analysis. A considerably improved PL quenching was detected for the nanorods and suggested a result of electronic coupling between the high-aspect-ratio CdS nanorods and the conducting polymer matrix. A photovoltaic device consisting of CdS nanorods with aspect ratio of ea. 16 and the conjugated polymer poly(3-hexylthiophene) was well assembled and showed a power conversion efficiency of as high as 2.9% under air mass (AM) 1.5 global solar conditions.