The asymmetric unit of the title compound, C(16)H(23)ClN(2)O, comtains two independent mol-ecules in which the fused-ring systems are essentially planar, the largest deviation from the mean plane of each mol-ecule being 0.011 (2) Å and 0.016 (2) Å. The benzimidazole rings of the two mol-ecules make a dihedral angle of 66.65 (7)°. The nonyl substituents are almost perpendicular to the benzimidazole planes [C-N-C-C tosrsion angles = 96.0 (3) and 81.0 (2)°]. In the crystal, each independent molecule forms an inversion dimer via a pair of N-H⋯O hydrogen bonds. In one of the independent molecules, the terminal -CH(2)-CH(3) group of the alkyl chain is disordered over two sets of sites with a refined occupancy ratio of 0.746 (7):0.254 (7).