ABSTRACTHeterocyclic compounds are widely distributed in nature and have played a vital role in synthetic organic chemistry. Five membered heterocycles, an important class of heterocyclic compounds, have been frequently synthesized and find a diverse range of applications in chemistry, biology and biochemistry of both pharmacological and chemical importance. Palladium-catalyzed cyclisation of different enynethiols has afforded a series of substituted thiophenes. The substrates, (Z)-2-en-4-yne-1- thiols, undergo cyclo isomerisation in dimethyl acetamide in the presence of catalytic amounts of PdI2 along with KI, to yield corresponding thiophenes 4 . Chiral imidazoles have been synthesized by thio-Ugi reaction . The method involves the treatment of thioamides with ammonia and cyclisation of the resulting substituted amidines in aqueous hydrochloric acid to afford corresponding imidazoles 11.This article will discuss on various synthetic pathways adopted for the synthesis of different five membered heterocycle derivatives and explore the mechanistic aspects apart from the recent applications of some unique compounds. Manuscript profile