The growth by metalorganic vapour phase epitaxy (MOVPE) of common anion strained layer superlattices (SLSs) based on the systems ZnSe-CdSe and ZnS-CdS, is reported. Such superlattictes have good structural and optical properties when grown at a temperature of 300-degrees-C. At higher growth temperatures, these properties deteriorate due to cation diffusion between adjacent layers of the structure and eventually, at 500-degrees-C, intermixed alloys form.