The book entitled "Pharmacological Study of Bio active Hetero cyclic compounds" has been divided into 3 chapters. Chapter I is a brief review on Isolation, characterization of bio active compounds from Muntingia calabura- a pharmacological study. Chapter II depicts an introduction to heterocyclic compounds and Synthesis, In vitro and In silico studies of 2-(3, 5-dimethyl-1-phenyl-1H-4-pyrazolyl)-3-(aryl/heteroaryl)-1,3-thiazolidin-4-ones. Chapter III describes Synthesis and In vitro studies of 2-(1-(Aryl) ethyl)-1-(2-(diethyl amino) ethyl)-1H-benzo[d]imidazol-5-amine moieties.