AbstractThe cobalt(III) chelates of 1‐nitroso‐2‐naphthol, 5‐methoxy‐2‐nitrosophenol, 4‐chloro‐2‐nitrosophenol and 4‐bromo‐2‐nitrosophenol and the Ni(II) chelates of 2,4‐dinitrosoresorcinol, 1‐nitroso‐2‐naphthol, 5‐methoxy‐2‐nitrosophenol, 4‐chloro‐2‐nitrosophenol were obtained in a crystalline form by the interaction of Co(II) and Ni(II) salts with the ligands or their sodium salts. The electronic spectra of nickel chelates were solvent and temperature dependent wh