Cuprous iodide (CuI) crystals are grown by slow evaporation technique in three different solvents. Large CuI single crystals with dimensions of 7.5 mm x 5 mm x 3 mm are obtained in pure acetonitrile solvent at 40 degrees C. The as-grown crystals are analyzed by X-ray diffraction, energy-dispersive X-ray analysis, differential scanning calorimetry, current-voltage characteristic and photoluminescence spectrum. The results show that the Cut crystal has the zinc-blende structure with no secondary phase. The elemental Cu/I ratio is 1.09:1. The melting point of the crystal is 875 K and two phase transitions occur from room temperature to its melting point. The electrical conductivity of CuI platelet crystal is in the range of 1.11-2.38 Omega(-1) cm(-1). Under ultraviolet excitation, the Cut crystals exhibit three emission bands with peak positions at 426, 529 and 671 nm. The nature of the luminescence is discussed. Crown Copyright (C) 2010 Published by Elsevier Ltd. All rights reserved.