Coumarins are a group of important natural compounds possessing multiple biological activities such as anti-bacterial, anti-fungal, anti-coagulant, anti-tubercular, anti-tumour, analgesic, anti-inflammatory and anti-HIV properties. They are also widely used as additives to food and cosmetics and optical brightening agents. This book deals with the synthesize of new coumarin derivatives by substitution at the third position of hetero-cyclic ring system for novel analgesic and anti-inflammatory agent with minimum toxicity and high potency.