In the title compound, C(11)H(9)ClN(4)O(2), the dihedral angle between the aromatic rings is 79.67 (8)°. π-π stacking between centrosymmetrically related pairs of pyrimidine rings occurs along [100] [centroid-centroid separations = 3.4572 (8) and 3.5433 (7) Å].