1-(Prop-2-ynyl)-1H-benzimidazol-2(3H)-one

The benzimidazolone part of the title molecule, C10H8N2O, is almost planar [r.m.s. deviation = 0.014 (1) ] and the NCH2C[triple-bond]CH group forms a dihedral angle of 67.95 (6)° with its best plane. In the crystal, molecules form inversion dimers via pairs of N—H...O hydrogen bonds. C—H...O interactions connect the dimers, forming a two-dimensional polymeric network parallel to (100).