In this paper, Cu-2(FexZn1-x)SnS4 nanocrystals were synthesized by a microwave irradiation assisted solvothermal method. The properties of Cu-2(FexZn1-x)SnS4 nanocrystals were studied by X-ray diffraction, Raman spectroscopy, scanning electron microscopy, transmission electron microscopy, and UV-vis spectroscopy. The results showed that as-synthesized Cu-2(FexZn1-x)SnS4 nanocrystals had a single phase and stoichiometric composition. The average crystalline size increased with increasing x. Moreover, the band gaps of Cu-2(FexZn1-x)SnS4 nanocrystals decreased with increasing x. (C) 2014 The Society of Powder Technology Japan. Published by Elsevier B. V. and The Society of Powder Technology Japan. All rights reserved.