In the title compound, C(20)H(15)NO, the heterotricycle is essential planar [maximum deviation = 0.0790 (5) Å] and makes a dihedral angle of 50.70 (2)° with the benzene ring. The formyl group is almost coplanar with the tricyclic ring, the C-C-C-O torsion angle being -0.78 (13)°.