In situ growth of cadmium sulfide (CdS) quantum dots (QDs) was achieved directly through solvent-assisted grafting in the self-assembled templates of amphiphilic all conjugated diblock copolythiophene, poly(3-hexylthiophene)-b-poly(3-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)methylthiophene) (P3HT-b-P3TEGT) and gas solid reaction. Such diblock polymer templates allowed a desired amount of cadmium sulfide salt (Cd(Ac)(2)) to easily accomplish dispersion and self-assembly via controlled assembling block copolymers in selective solvents. After P3HT-b-P3TEGT polymer templates grafted with Cd2+ precursor (P3HT-b-P3TEGT/Cd2+) reacting in hydrogen sulfide (H2S) gas, one-dimensional core shell nanobeams network P3HT-b-P3TEG/CdS (donor acceptor) was formed with excellent phase separation between P3HT-b-P3TEGT crystalline domains and inorganic CdS QDs domains at nanoscales, which was driven by the interaction between oxygen atoms of ethylene oxide side chains and Cd2+ ions, and the thermodynamic equilibrium between polymer chains deformation. The one-dimensional wire-like nanostructure were highly desirable for the active layers in photovoltaic devices as providing high carrier mobility, large interfacial area between electron donor and acceptor, and highly efficient transport pathways to improve the power conversion efficiency (PCE) of hybrid bulk heterojunction solar cells.