The Dilute Magnetic Semiconductors (DMSs) are semiconducting materials in which a fraction of the host cations can be substitutionally replaced by transition metal ions (Fe, Co, Ni etc.). They acquire both semiconducting as well as magnetic properties. They are promising materials for applications as spinitronics and optoelectronics. II-VI group semiconductors of periodic table generally covers the whole spectrum ranging from ultraviolet (UV) to far infrared (IR) and also has higher solubility of magnetic atoms. Authors have chosen Cadmium Sulphide (CdS) with different concentration of Cobalt (Co) doped due to they are highly multifunctional owing to their contemporaneous magnetic, semiconducting, electromechanical, structural and optical properties. This book therefore provide information about synthesis process of Co doped CdS nanoparticles as well as its structural properties by X-ray peak broadening.