2,3-Tri­methyl­ene-7,8-di­hydro­pyrrolo­[1,2-a]thieno[2,3-d]pyrimidin-4(6H)-one

The title mol­ecule, C₁₂H₁₂N₂OS, is planar, with an r.m.s. deviation of 0.04 Å. In the crystal, the N atom adjacent to the carbonyl group is sp²-hybridized. The crystal structure is stabilized by π–π stacking inter­actions observed between thio­phene and pyrimidinone rings of c-glide-related mol­ecules [centroid–centroid distance = 3.9554 (13) Å] and by C—H...π inter­actions, forming an infinite chain along the c-axis direction.