9-Allyl-9H-carbazole-3,6-dicarbaldehyde.

In the title mol-ecule, C(17)H(13)NO(2), the allyl group is almost perpendicular to the carbazole mean plane, with a dihedral angle of 89.0 (2)°. In the crystal, nonclassical C-H⋯O hydrogen bonds link the mol-ecules into corrugated sheets parallel to the bc plane. Weak inter-molecular π-π inter-actions are observed between the benzene rings [centroid-centroid distance = 3.874 (4) Å] from neighbouring sheets.