We have focused on extreme synthetic potential of acid hydrazides for synthesis of polyfunctional heterocyclic compounds which have been reported in vogue. Many pharmaceutically active heterocycles have been synthesised by using acid hydrazides particularly concerning with many name reaction and rearrangements. Synthesis of various derivatives of acid hydrazides from lactones, cyclic anhydrides etc. work as key synthon components for preparative compounds. Various reagents react with hydrazides for the preparation of heterocyclic compounds under pH effective conditions. It includes a significant feature to develop environmentally benign microwave-irradiated procedure for heterocyclic synthesis. Acid hydrazides can be essential building blocks in combinatorial synthesis of functionalized heterocyclic compounds which are used for design of novel pharmaceutical drugs. In several cases, reports on the low yield of bioactive heterocycles can be solved by prospective synthetic chemistswith constant investigation, new methodology and elaborated experimental techniques. This will contribute towards a library of poly-functional heterocycles as a useful aid in medicinal chemistry.