Quinazolinones form a large group among the pharmacologically active chemical moieties and are generally of little toxicity without serious side effects to the human body. Quinazolinones are versatile nitrogen heterocyclic compounds, displaying a broad spectrum of biological and pharmacological activities in animal as well as in human systems. The chemistry and pharmacology of quinazolinones have been of great interest to medicinal chemists. In 1885, Weddige synthesized the first quinazolone and named it anhydroformylorthoamidobenzamide. Later on, extensive work on this nucleus was done for the amelioration of human suffering from various diseases and many drugs incorporating this nucleus were developed.