This book includes three chapters. First chapter is concerned with the synthesis and biological activities of indazoles and second chapter included the synthesis of oxo-ketenedithioacetals, chalcones, dimethylamino methylene ketones, enolic ethers derivatives of carbazole (and azacarbazole) anuulated pyrazole which have been used as precursors in the synthesis of a variety of fused heterocyclic systems. Third chapter describes the results which have emanated, on screening the antimicrobial and antifungal activity of a few selected synthesized compounds.