In present work, we have successfully deposited nanosphere-like pure CdSe (NSC) and Mn:CdSe thin films onto FTO coated glass substrate and stainless steel substrates by facile electrochemical method. X-ray diffraction (XRD) study revealed that the films are polycrystalline in nature exhibiting hexagonal crystal structure. SEM analysis showed the fabrication of 3D nanosphere-like nanostructure for CdSe whereas nanonest-like nanostructures for Mn:CdSe, composed of number of sphere like thin rounded nanograins. Moreover, the optical absorption study revealed the decrease in band gap energy from 1.81 eV to 1.60 eV and water contact angle of CdSe and Mn:CdSe thin film lays in the hydrophilic regime which enhances the intimate contact at electrode/electrolyte interface. The photo-conversion efficiency and fill factor of this photo-electrochemical cell are found to be 0.67%, 0.37%, and 0.71%, 0.53%, respectively. (c) 2014 Elsevier B.V. All rights reserved.