Sulfonamides are the commonly used antibiotics, which are used in the combination with other antibiotics to enhance their effect. They are absorbed in the intestine and are widely distributed into the tissues. Sulfonamides inhibit the growth of bacteria by reverse inhibition and block the cycle of folic acid synthesis while they are effective against only those bacteria which produce folic acid intracellular. This book discusses about the synthesis of sulfonamides their characterization with modern instruments and their importance. The antibacterial activity which increases their importance has also been discussed. This book is divided into different chapters which enables the readers to understand this book easily. Chapter 1 covers the general introduction of sulfonamides and techniques used for characterization and chapter 2 explains the previous scientific work done on sulfonamides. Chapter 3 contains the experimental work while chapter 4 discusses the results obtained. Figures, tables and schemes are used to make it easier for readers.