5,6,7,7a-Tetrahydrothieno[3,2-c]pyridine-2(4H)-one hydrochloride is a heterocyclic compound that features a thiophene ring fused with a pyridine ring, creating a unique bicyclic structure. This compound belongs to the class of thienopyridines, which are known for their diverse biological activities and have been extensively studied in the fields of medicinal chemistry and drug discovery.