This book contain ten chapters. First chapter for introduction of drugs and chemistry. Second chapter introduce about Chalcone. Third, fourth and fifth chapters introduce about Pyridine, pyrimidine, Thiourea derivatives. Sixth chapter tells about synthetic scheme for Pyrido-pyrimidine-2-thione. Chapter seven and eight for characteristic data and anti microbial data of Pyrido-pyrimidine-2-thione derivatives. Chapter nine tells about result and discussion. Chapter ten briefly conclude relative activity of all derivatives against microbial. This book is useful for new research students for synthesis of various new chemical entity for various disease.