In the title compound, C(20)H(19)N(3)O(3), the inter-planar angle between the benzimidazole unit and the quinoline unit is 25.1 (2)°. Two different hydrogen bonds involving the hydr-oxy group and the imidazole unit are present. An intra-molecular N-H⋯O hydrogen bond links the hydr-oxy group of the side chain with the imidazole unit, forming a 12-membered ring, and an inter-molecular O-H⋯N hydrogen bond links the mol-ecules, forming chains in the crystallographic b direction.