The present book deals with the phenomena of opto-electronic and elastic properties of binary (II-VI and III-V) semiconductors having tetrahedral structure. The binary semiconductors taken for study belong to Zinc-blende and Wurtzite structure. In the present book we have developed a simple model based on plasma oscillations theory of solids, which require minimum knowledge of the semiconductors to investigate opto-electronic and elastic properties. The physical concept taken for this purpose is that the plasmon energy is directly or indirectly related with many opto-electronic and elastic parameters and can be obtained easily due to its dependence on effective number of valence electrons. The main advantage of the proposed model is the simplicity of the formulae and it can be used to predict the reliable values of optoelectronic and elastic parameters, even for those semiconductors whose experimental measurements have not yet been made.