The asymmetric unit of the title compound, C(20)H(15)N(3)O, contains two independent mol-ecules, each of which is disordered over two sets of sites corresponding to a rotation of approximately 180° of the dihydro-benzimidazoquinazoline moiety, with refined site occupancies of 0.7479 (13) and 0.2521 (12) for both mol-ecules. The pyrimidine rings are in sofa conformations. In one mol-ecule, the hy-droxy-substituted benzene ring forms dihedral angles of 83.9 (3) and 82.4 (4)° for the major and minor components, respectively, with the mean plane of the benzimidazole ring system. The corres-ponding dihedral angles in the other mol-ecule are 88.31 (14) and 85.8 (6)°. In the crystal, mol-ecules are linked via inter-molecular O-H⋯N and N-H.·O hydrogen bonds into chains along .