The reaction between [M(acac)3] (M = Fe, Co, acac = acetylacetonate) and the diamino-bis(phenol) pro-ligands (2-OH-3,5-tBu2-C6H2CH2)2NCH2(2-NC5H4) (H21) and (2-OH-5-tBu-C6H3CH2)2NCH2CH2CH2N(CH3)2 (H22) afforded the [κ4-(N2,O2)M(acac)] complexes [Fe(1)(acac)] (3), [Fe(2)(acac)] (4), [Co(1)(acac)] (5) and [Co(2)(acac)] (6) in moderate yields after crystallization. The proposed formulas were supported by various analytical data (ESI-MS, FT-IR, EA, NMR), and the molecular structure of all complexes was confirmed by X-ray diffraction studies. In each octahedral complex, the diamino-bis(phenolate) ligand (1 or 2) acts as a tetradentate ligand and the coordination sphere is completed by one chelating κ2-O2 acac ligand. Although the previously reported ligand 1 and the new ligand 2 are very similar, their coordination to the FeIII(acac) or CoIII(acac) moieties varies by the arrangement of the donor atoms. While the Ophenolate donor atoms of ligand 1 were found cis to each other in the FeIII complex 3, they are trans in the CoIII complex 5, and vice versa for ligand 2. Since each ligand, 1 and 2, exhibits both configuration, this structural curiosity cannot be easily explained on the basis of steric factors, i.e. ortho-substituents or N,N′-linker length.