In the title compound, C21H19N3O5, the phthalimide and benzamidazole ring systems are linked by a propyl chain. The benzamidazole unit also carries an eth-oxy-carbonyl substit-uent. The phthalimido and benzimidazole ring systems are essentially planar, the maximum deviations from their mean planes being 0.008 (2) and 0.020 (2) Å, respectively. The two ring systems are almost orthogonal to one another, making a dihedral angle of 82.37 (8)°. In the crystal, C-H⋯O hydrogen bonds and C-H⋯π contacts stack the mol-ecules along the b axis.