In the recent past, Heterocycles becomes an important class of compounds, making up more than half of all known organic compounds. Heterocycles are present in a wide variety of drugs, most vitamins, many natural products, biomolecules, and biologically active compounds, including antimicrobial, anticancer, anti-inflammatory, antidepressant, antimalarial, anti-HIV, antiviral, plant activators agents. A major aim of this book was to provide recent literature regarding the biological prospective of heterocycles compounds. The current book is compilation of biological potentials of heterocylic compounds like thiazole and 2-azetidinone.