When silicon complexes, coordinated with ligands, demonstrate enhanced biological properties compared to free silicon. Silicon complexes particularly N, O, and S donor exhibit improve stability, solubility, and targeted reactivity, making them suitable for pharmacological applications, including antimicrobial, insecticidal, antifertility, nematicidal, anticarcinogenic, antitumor, anti-inflammatory, and anticancer activities. This book provides a comprehensive overview of silicon(IV) complexes, which predominantly adopt penta-, hexa-, and hepta-coordinate geometries. These species are typically synthesized by reacting silicon-based precursors, such as silicon chlorides, alkoxides, or acetates, with bi- or multidentate ligands containing nitrogen, oxygen, or sulfur donor atoms. Overall, this book not only highlights advances in synthetic strategies but also serves useful spectral data and analytical details in form of tables. In future the book is helpful for researchers.