In the crystal structure of the title compound, C 23 H 19 N 5 O 3 ·0.58C 2 H 6 OS·0.42C 2 H 3 N, prepared by the azo coupling of the 4-nitro-phenyl-diazo-nium salt with 3a-( p -tol-yl)-2,3,3a,4-tetra-hydro-1 H -benzo[ d ]pyrrolo-[1,2- a ]imidazol-1-one, the azo mol-ecules are linked by N-H⋯O hydrogen bonds into chains along the a -axis direction, and by the π-π inter-action into [101] chains. The dimethyl sulfoxide and aceto-nitrile solvent mol-ecules occupy the same positions, with populations of 0.585 (3) and 0.415 (3), respectively. These mol-ecules take part in C-H⋯O(N) and C-H⋯π contacts. The energy of the π-π inter-actions was estimated using DFT calculations. The Hirshfeld mol-ecular surface analysis revealed the positions of the most important inter-molecular contacts, such as hydrogen bonds and π-π inter-actions.