(E,E)-1,2-Bis[3-(prop-2-yn-1-yl­oxy)benzyl­idene]hydrazine

The mol­ecule of the title compound, C₂₀H₁₆N₂O₂, is centrosymmetric, the inversion center being located at the mid-point of the central azine bond. The conformation around the C=N bond is E. The whole mol­ecule (except for the H atoms) is essentially planar, with an r.m.s. deviation of 0.07 Å. In the crystal, mol­ecules are linked head-to-tail by pairs of C—H...O hydrogen bonds, forming inversion dimers, and resulting in the formation of chains propagating along [011].

2,2′-Diethoxy-4,4′-[(E,E)-hydrazine­diyl­idenebis(methanylylidene)]diphenol

The complete molecule of the title compound, C₁₈H₂₀N₂O₄, is generated by inversion symmetry. The conformation around the C=N bond is E. With the exception of the eth­oxy substituent, the mol­ecule is essentially planar with an r.m.s. deviation of 0.0455 Å. In the crystal, mol­ecules are linked by O—H...N hydrogen bonds into a two-dimensional supra­molecular network parallel to the bc plane.