This book describes the synthesis and characterization, Biological evaluation of N-allyl and N-benzyl-quinazolinones , N-Substituted 4-(4-chloro-phenethyl)-3-methoxypyridin-2(1H)-ones, 3-Hydroxy-1-methyl-4-[4-(substituted pyridin-2-yloxy)phenethyl]pyridin-2(1H)-ones, 1-cyclopropyl-6-fluoro-8-methoxy-7-susbstituted-4-oxo-1,4-dihydroquinolin-3-carboxylic acids, and N-(1-Cyclopropyl)-6-fluoro-7-[4-[2-arylacetyl]-[1-piperazinyl]-4-oxo-1,4-dihydroquinoline-3-carboxylic acids. All the moieties are biologically potent and medicinally significant.