This paper discloses that visible light can trigger efficiently the oxy-chlorination of cyclohexane by some metal chlorides at ambient temperature under N-2 atmosphere. Among the metal chlorides examined, only a few metal chlorides with easily changeable valence such as VOCl3, CuCl2 center dot 2H(2)O and FeCl3 center dot 6H(2)O were found to be efficient chlorinating agents for this photoreaction in acetonitrile or acetone, providing mono- and di-chlorinated cyclohexane as main products, with concomitant formation of a small amount of cyclohexene, cyclohexanol and cyclohexanone. CuCl2 center dot 2H(2)O was the most active chlorinating agent for this photoreaction, but provided an appreciable amount of the non-chlorinated products. FeCl3 center dot 6H(2)O possessed the best selectivity for the chlorinated products. In addition, it was found that a suitable amount of concentrated HCl was capable of realizing the visible light-driven CuCl2 center dot 2H(2)O or the UV-driven FeCl3 center dot 6H(2)O to catalyze photo-oxy-chlorination of cyclohexane under air, providing a high chlorination efficiency (turnover number (TON), 2.46 for CuCl2 center dot 2H(2)O and 4.66 for FeCl3 center dot 6H(2)O). This is likely because the HCl can itself be used as a chlorinating agent; on the other hand, it also efficiently promotes the photoredox cycling of CuCl2 or FeCl3, as supported by UV-vis spectra. Based on these findings, a free radical mechanism for the present photo-oxy-chlorination system was proposed. (C) 2013 Elsevier B.V. All rights reserved.