The ZnSe and ZnSSe single crystals have been grown by chemical vapour transport (CVT) with iodine as a transporting agent. The source and growth temperatures of the reactor are maintained at 850 degrees C and 900 degrees C respectively using the two zone horizontal resistive heating furnace. The grown crystals are characterised by structural, surface morphological and optical properties. The XRD pattern shows that the peaks due to reflection from (111), (220) and (311) planes belong to the cubic zinc-blend structure. The composition of grown ZnSe crystal has been determined by EDXRF analysis as Zn (52.5%) and Se (47.5%). The XPS study of grown ZnSe single crystal has been studied. The HRSEM images reveal the step, spiral and triangular patterns. The optical absorption study reveals the absorption cut off wavelength as 483 nm (2.57 eV) for ZnSe and 441 nm (2.81 eV) for ZnSSe crystals. The photoluminescence studies reveal the band edge emission and defect level emissions of ZnSe and ZnSSe single crystals. (C) 2013 Elsevier B.V. All rights reserved.