An investigation of the solid-state microwave synthetic method was performed using AgInSe2 as a model system. Sample volume, irradiation time and grinding time of reactants were investigated in order to determine the effect that these variables have on the phase purity of the reaction product. In addition, the reaction mechanism was probed by carrying out irradiation experiments using the constituent elements and binary mixtures. AgInSe2 samples synthesized via solid-state microwave irradiation were compared to a sample that was synthesized via high-temperature solid-state synthesis in a furnace. Powder X-ray diffraction, differential thermal analysis and diffuse reflectance spectroscopy in the UV/vis/near IR region were used to characterize all reaction products. (C) 2006 Elsevier Ltd. All rights reserved.