Microhardness and optical absorption measurements have been carried out for the CdS single crystals grown both by sublimation (in vacuum atmosphere) and hydrogen transport techniques. There is a reduction in hardness, fracture toughness and optical absorption of the CdS single crystals when hydrogen is used as the transporting agent. The microhardness measurement has also been carried out for the sublimation grown CdSe single crystals which showed higher hardness and fracture toughness values compared to sublimation grown CdS single crystal.