Nine ortho-hydroxy Schiff base ligands, ( 1)–( 9), were synthesized and characterized by chemical analysis, mass spectrometry, 1H and 13C NMR spectroscopy. The crystal and molecular structures of compounds ( 1), ( 3), ( 5), ( 7), ( 8) and ( 9) were determined. The solid state X-ray diffraction studies show that compounds ( 5) and ( 8) are in the keto–amine tautomeric form, while ( 1), ( 3), ( 7) and ( 9) are found as phenol–imine tautomers. Moreover, studies in the solution phase by 1H and 13C NMR spectroscopy indicate that compounds ( 2), ( 5) and ( 8) are found as keto–amine tautomers, while ( 1), ( 3), ( 4), ( 6), ( 7) and ( 9) are found as phenol–imine tautomers. Furthermore, ab initio calculations at the HF/6-31G ∗ level with full optimization of geometry, performed for both tautomers of ( 1) and ( 5), agree with the observed behavior in solution and solid state of these compounds.