Synthesis and crystal structure of 1-hy-droxy-8-methyl-9-carbazole-2-carbaldehyde.

Two crystallographically independent mol-ecules are present in the asymmetric unit of the title compound, CHNO, with virtually identical geometries. The carbazole units are planar. The hy-droxy group at position 1, carbaldehyde group at position 2, and methyl group at position 8 (with the exception of two H atoms) are coplanar with the attached benzene rings. The dihedral angle between the two benzene rings is 2.20 (9)° in mol-ecule and 2.01 (9)° in mol-ecule . The pyrrole ring makes dihedral angles of 0.82 (10) and 1.40 (10)° [0.84 (10) and 1.18 (10)° in mol-ecule ] with the (-CH)-substituted and (-OH and -CHO) substituted benzene rings, respectively. The mol-ecular structure is stabilized by the intra-molecular O-H⋯O hydrogen bonds, while the crystal structure features N-H⋯O and C-H⋯O hydrogen bonds. A range of π-π contacts further stabilizes the crystal structure.