π-stacking and C—X...D (X = H, NO₂; D = O, π) inter­actions in the crystal network of both C—H...N and π-stacked dimers of 1,2-bis­(4-bromo­phenyl)-1H-benzimidazole and 2-(4-bromo­phenyl)-1-(4-nitro­phenyl)-1H-benzimidazole

Mol­ecules of two substituted 1H-benzimidazoles are arranged in dimeric units through C—H...N and parallel-displaced π-stacking inter­actions. The mol­ecular packing of the dimers arises by the concurrence of a diverse set of weak inter­molecular C—X...D (X = H, NO₂; D = O, π) inter­actions.