The tricyclic aromatic ring system of the title compound, C15H9Cl2N, is essentially planar (r.m.s. deviation = 0.002 angstrom). The two Cl atoms lie slightly out of the plane of the carbazole ring system, with the C-Cl bonds forming angles of 1.23 (8) and 1.14 (8) degrees with the plane. The acetylene group has a syn orientation with respect to the ring system. In the crystal, no weak hydrogen bonds nor any pi-pi stacking interactions are observed.