In this work, a novel organic-inorganic heterostructured photocatalyst: porous graphitic carbon nitride (g-C3N4) hybrid with copper sulfide (CuS) had been synthesized via a precipitation-deposition method at low temperature for the first time. UV-vis spectroscopy revealed the porous g-C3N4/CuS nanocomposites showed a strong and broad visible light absorption. Furthermore, the g-C3N4/CuS nanocomposites showed higher photocatalytic activity in the photodegradation of various organic dyes than that of pure g-C3N4 and CuS, and the selected sample of g-C3N4/CuS-2 exhibited the best photocatalytic activity under visible light. The good photocatalytic activity could be ascribed to the matching of the g-C3N4 and CuS band gap energies. Besides, photoluminescent spectra and photoelectrochemical measurements also proved that the CuS/g-C3N4 could greatly enhance the charge generation and suppress the charge recombination of photogenerated carriers. According to the experimental result, a possible photocatalytic mechanism has been proposed. Due to the high stability, the porous g-C3N4/CuS could be applied in the field of environmental remediation. Our work highlights that coupling semiconductors with well matched band energies provides a facile way to improve the photocatalytic activity. (C) 2016 Elsevier Inc. All rights reserved.