In this study, we demonstrate a facile in situ synthetic strategy to fabricate self-assembled organic/inorganic hybrid nanowires, wherein a "pre-crystallization" approach was first utilized to co-organize P3HT molecules and zinc precursors into highly elongated nanowires, followed by a thermal oxidation treatment to directly grow ZnO nanocrystals on the existing nanofibrillar template. By further thermal annealing the ZnO embossed hybrid nanowires, a unique superhighway-like architecture which composed of alternating parallel channels of P3HT nanofibrils and ZnO nanocrystals could be further obtained. This donor/acceptor (D/A) parallel-channel structure gave access to the improvements in the exciton dissociation and charge transport, thereby enhancing photoluminescence quenching, charge transport, and device performance. The photovoltaic devices with the D/A parallel-lane structure gave a high PCE of 0.61% as compared to only 0.07% from a conventional P3HT/ZnO bulk heterojuction solar cell. Our approach offers a versatile route to coassemble inorganic nanocrystals with pi-conjugated polymer hosts, forming uniform one-dimensional hybrid nanochannels potentially useful in optoelectronic applications.