Heterocyclic compounds are emerging as potential molecules in the fight of the microbial diseases of humans and animals. These compounds have got greater applications in agriculture also. The present book dealt with the synthesis of azo-lactone derivatives and their application towards microbial pathogenic activity. The azo-lactone derivatives include Thiazolone, imidazolyl azetidinones and thiazolyl quinoline/ thiazolyl quinazolones which have synthesized through Schiff base condensation of their counter aldehyde/ketones. These newly synthesized compounds were bio-evaluated for their anti-viral, anti-bacterial and antifungal activities in vitro. Among the all reported azo-lactone derivatives the class of compounds having thiazolyl quinoline moiety gave the best signature with structure property relationship. Author thought that the reader and researcher in the area will get a new insight toward the study of such compounds.