5',11'-Dihydro­dispiro­[cyclo­hexane-1,6'-indolo[3,2-b]carbazole-12',1''-cyclo­hexa­ne]

The title compound, C₂₈H₃₀N₂, is a symmetrical 2:2 product from the condensation of indole and cyclo­hexa­none. It is the only reported 5,11-dihydro­indolo[3,2-b]carbazole compound in which the spiro atoms are quaternary C atoms. Crystals were grown by vapor diffusion in a three-zone electric furnace. The mol­ecule resides on a crystallographic inversion center. The cyclo­hexyl rings are in a slightly distorted chair conformation, whereas the indole units and the spiro-carbons are coplanar within 0.014 Å.