In the mol-ecule of the title compound, C(16)H(20)N(4), the 1,3-diazinane ring adopts a chair conformation and the dihedral angle formed by the pyridine rings is 78.64 (8)°. The mol-ecular conformation is stabilized by an intra-molecular C-H⋯N hydrogen bond, forming an S(6) ring motif. In the crystal, centrosymmetrically related mol-ecules are linked into dimers by pairs of N-H⋯N hydrogen bonds, generating rings of R(2) (2)(10) graph-set motif.