In modern world, thin film technology are widely used in scientific and commercial applications due to their significant electrical, optical, mechanical and thermal properties. Semiconducting thin film find wide applications in the fabrication of solid state devices such as photo conductors and solar cells.Zinc doped cadmium sulphide (ZnxCd1-xS) compound is one of the promising n-type direct band gap semiconductor materials, because of its tunable energy gap and the lattice parameters. The band gap energy of ZnxCd1-xS is controlled by the change of zinc composition in order to suit the material properties with that of absorb-er material in solar cells. This book basically focuses on how the doping phenomena alter the optical and structural properties of ZnCdS thin films developed by Thermal evaporation techniques. Optical and Structural properties of ZnxCd1-xS analyzed through UV-Visible Spectrophotometry and XRD at various composition of x.