This book contains various aspects dealing with studies for the synthesis of macrolide natural products, Stagonolide-G, and Hygrocin-A. It also contains synthesis and bioevaluation of Nitrogen containing Heterocyclic compounds like tetrazoles,thieno pyridines,thieno quinolines and Isatins. The new heterocyclic compounds tetrazoles and thieno compounds have shown significant anticancer and antimicrobial activities respectively. DNA binding studies have been carried out and illustrated as a part. Single X-ray crystallographic data were included for confirmation of structure of some compounds. All the compounds were well characterized by full spectoscopic data like NMR, IR, Mass etc. and spectras were included for the selected compounds. Some interesting synthetic methodologies also included as appendix in the book.