9-Methyl-3-phenyldiazenyl-9H-carbazole: X-ray and DFT-calculated structures.

The title compound, C19H15N3, was prepared by condensation of 3-nitroso­carbazole and aniline with subsequent methyl­ation. The structure is built up of stacks of almost planar mol­ecules. Density functional theory (DFT) calculations predict a completely planar conformation, different from that observed in the crystal lattice. HOMA (harmonic oscillator model of aromaticity) indices, calculated for three aromatic rings, demonstrate the small influence of the azo substituent on π electrons in the carbazole system.