The electronic structure of tetramethoxyformaldazine was investigated by photoelectron spectroscopy and MNDO calcns. Some conformational properties and the mol. structure were analyzed by vibrational spectroscopy, MNDO calcns., and x-ray crystallog. The compd. is monoclinic, space group P21/n, with a 7.108(1), b 6.252(1), c 9.983(2) .ANG., and b 99.12(3) Deg; Z = 2. Final R = 0.043. The at. coordinates, bond lengths and angles are given. The compd. is planar and centrosym. (mol. symmetry C2h). Correlations between electronic structure and conformational properties of azines with different substituents are discussed on the basis of a qual. stereoelectronic model.