Single and multilayer structures of CdS and CdSe have been grown on GaAs by MOCVD. Pure hexagonal CdS layers have been grown on the (111) A surface whereas CdSe was found to grow as a mixture of cubic and hexagonal phases. Multilayers of CdS/CdSe were grown onto (111)A GaAs on which CdS was used as a buffer layer. Transmission electron microscopy of the multilayers shows both the CdS and CdSe layers were hexagonal with no twinning and had abrupt interfaces. Low temperature photoluminescence of the layers shows a strong infra-red emission band. A series of structures with a repetition period of 100Å but with different layer thicknesses shows shifts in the wavelength of this infra-red emission band which is accounted for in terms of a type II band structure in which lattice strain and confinement effects are included.