An efficient photoanode of Zn-Cu: doped nanostructure CdS film has been fabricated by a very simple and commercially usable chemical bath deposition methodology. The electrodes of various sizes were deposited, those ranged from 10 x 10 mm to 100 x 100 mm. Physicochemical property of the film is investigated in-depth for the photo-electrochemical (PEC) hydrogen production and electric-power generation application. Especially, we studied the effect of Zn and Cu co-doping in the hexagonal CdS-lattice w.r.t. the structural, optical and PEC properties of the nanostructure film. Zn-doping induces an increase in the absorption of visible light photons. The doping enhances the photocurrent by twice as to the undoped, and generates a net photocurrent of -817 mu A/cm(2), at a very low applied potential of 0.1 V/SCE, in contrast to 366 mu A/cm(2) of its undoped counterpart. Electrochemical impedance spectroscopy demonstrated that the reduced e-h recombination is responsible for the superior performance of the electrodes. PEC cell fabricated by these electrodes showed a maximum hydrogen generation rate of -6.74 mu mol/h as compared to 0.58 mu mol/h from undoped counterpart; Further a photo to electric-power conversion efficiency of similar to 0.16% has been achieved even at low biasing potential of 0.1 V/SCE under AM 1.5 solar simulated illumination. Undoped, Zn doped and Cu co-doped films are highly useful for dual applications of "solar power-generation" and "solar hydrogen-generation", revealing that the Zn doped PEC solar cell is most efficient system for the hydrogen generation even at a very low voltage bias of 0.1 V/SCE. (C) 2016 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved.