Electrochemical synthesis of photoactive cadmium-indium-selenide (CdIn2Se4) thin films at ambient temperature was reported. The nanocrystalline nature and 1:2:4 elemental chemical stoichiometric ratio for Cd, In and Se were obtained from the X-ray diffraction and energy dispersive X-ray analysis, respectively. Irregular shaped islands of about 400-500 nm in sizes composed of large number of small (similar to 30-40 nm) spherical grains were confirmed from the atomic force microscopy and the scanning electron microscopy images. The photoelectrochemical measurement of CdIn2Se4 film electrode in presence of 1 M polysulphide electrolyte revealed 0.42% photoelectrochemical device conversion efficiency, under the light illumination intensity of 80 mW/cm(2). (c) 2007 Elsevier B.V. All rights reserved.