Crystallography deals with atoms, and when we get down to atoms, science is all unified! Knowledge of molecular structures is a prerequisite for rational drug design and structure based functional studies for effective therapeutic agents and drugs. Recently, Benzothiazole derivatives have received attention for their potent importance in organic chemistry and in the biological, pharmaceutical and industrial fields. This book provides a single-crystal X-ray diffraction study for a series of five Benzothiazole derivatives to elucidate their three dimensional structure aiming to establish the effect of the different substituted moieties on the stereochemical orientation within the whole structure. In addition, Tetrahydronaphthalene derivatives and their incorporation into heterocyclic rings are also of an increasing interest. In this book, a crystallographic study is devoted to confirm the suggested configuration of a Tetrahydronaphthalene derivative that is assumed to behave as an intermediate for the synthesis of biologically active derivatives. This book is useful for anyone who considers utilizing the investigated materials for synthesis as well as their diverse applications.