In the title mol-ecule, C12H8N2O2, the nitro group is tilted slightly with respect to the carbazole moiety [angle between the least-squares planes = 4.43 (9)°]. In the crystal, the mol-ecules are connected via pairs of N-H⋯O hydrogen bonds into dimers with -1 symmetry. The dimers in turn are arranged into layers parallel to (10-1).