The present book describes the Chemistry of new Quinoline/Pyrazole substituted Quinazolin-4-one derivatives. It describes conventional and microwave assisted synthesis and in vitro study of some Quinoline/Pyrazole substituted 4-(3H)-quinazolinone derivatives. The developed synthetic method was optimized mathematically by following Taguchi Orthogonal Array Design system. Some of the synthesized compounds have shown good Anti microbial activities, anti malarial activity. Attempts were also made to determine Structural Activity Relationship (SAR) amongst the compounds. We are sure that the book will be guide line for the researcher working in the field of medicinal chemistry.