The dinucleating bis(tetradentate) ligand susan [= 4,7‐dimethyl‐1,1,10,10‐tetra(2‐pyridylmethyl)‐1,4,7,10‐tetraazadecane] reacts with [Fe(OH2)6](BF4)2 to the complex [(susan){FeIIIF(µ‐O)FeIIIF}](BF4)2. In contrast, the reaction of the ligand derivative susan6‐Me with 6‐methylpyridyl instead of pyridyl donors with [Fe(OH2)6](BF4)2 results in the complexes [(susanMe){FeII(µ‐F)2FeII}](BF4)2 and [(susanMe){FeIIF(µ‐F)FeIIIF}](BF4)2. The synthesis of the µ‐oxo diferric complex [(susan6‐Me){FeIIIF(µ‐O)FeIIIF}]2+ requires the addition of H2O2 as oxidant. The best synthesis is the H2O2 oxidation of the new diferrous precursor [(susan6‐Me){FeII(µ‐F)2FeII}](ClO4)2. The introduction of the 6‐methylpyridine donors results in an elongation of the Fe–Npy bonds. The resulting lower electron donation is not compensated by the µ‐oxo bond but slightly by the Fe–Namine bonds. These structural changes are correlated with the νas(FeOFe) stretching mode, a smaller Mössbauer quadrupole splitting, a smaller ligand field splitting, a weaker antiferromagnetic exchange, and an anodic shift of the redox potentials. This destabilization of the ferric state correlates with the different reactivity of the diferrous precursors to the µ‐oxo diferric complexes: air for susan and H2O2 for for susan6‐Me. Structural analysis indicates a steric repulsion of the 6‐methyl group with the fluorido ligand in cis‐position as origin for the longer Fe–Npy bonds, which seems to be a general phenomenon.