The Schiff base N,N′-bis(2-hydroxy-3-methoxyphenylmethylidene)-2,6-pyridinediamine has been synthesized and characterized in the solid state and in solution using X-ray analysis, IR, UV/Vis, and NMR spectroscopy. Crystal data: C21H19N3O4, Mr = 377.39, orthorhombic, space group Pnc2, a = 4.9288(8), b = 8.8873(19), c = 20.870(5) A, V = 914.19(20) A3, Z = 2, R = 0.0387, Rw = 0.0530, 1845 independent reflections, 778 with I > 2σ(I). There are two intramolecular hydrogen bonds O—H-N between the hydroxyl and imino groups of 2.622(3) A. The enolimine form is found in the solid state and is also the predominant tautomeric form in solution. Comparison of the title compound with the structurally related N,N′-bis(salicylidene)-2,6-pyridinediamine and N,N′-bis(salicylidene)-2,3-pyridinediamine is given.