3-(9H-Carbazol-9-yl)-2H-chromen-2-one

The title compound, C(21)H(13)NO(2), was prepared as an example of a new synthesis of carbazoles from a cyclic dibenzo-iodo­lium salt via a twofold Pd-catalysed aryl­ation of a primary amine. The two essentially planar π-subsystems [maximum deviations from the mean square plane of 0.038 (2) Å in the carbazole and 0.059 (2) Å in the coumarine unit] open a dihedral angle of 63.05 (4)°. Two mol­ecules form a centrosymmetrical pair connected via π–π inter­actions between the pyrrole and pyrone rings [centroid–centroid distance = 3.882 (1) Å] and one benzene of the carbazole and the pyrone unit [centroid–centroid distance 3.824 (1) Å]. The lattice is stabilized by C—H⋯O bridging to both coumarin O atoms.