Pure CuInSe2 nanoparticles have been successfully synthesized via a solution method in the solvent of oleylamine. Anhydrous InCl3, CuCl, and Se powder were used as the starting materials. The CuInSe2 samples were characterized by XRD, TEM, and XPS techniques. It was found that tetragonal chalcopyrite structured CuInSe2 nanoparticles were obtained with temperature above 230 degrees C. Sample prepared at 200 degrees C possesses triangular morphology and a minute amount of In2Se3 coexists as intermediate. CuInSe2 nanoparticles with size of 20.2 +/- 0.4 nm were prepared at 230 degrees C and the narrow size distribution was ascribed to the employment of hot injection, which was better for homogeneous nucleation. Stable "ink" can be formed when the as-synthesized CuInSe2 nanoparticles were dispersed in organic solvents such as hexane and tolune, and such "ink" might have a practical application in CuInSe2-based solar cells. (C) 2012 Elsevier Ltd. All rights reserved.