AbstractThe synthesis and structural, mass spectrometric, FT‐IR, Mössbauer, and UV/Vis spectroscopic, electrochemical, and DC and AC magnetic properties of three [MnIII6FeIII]3+ (short for [{(talen)MnIII3}2{FeIII(CN)6}]3+) compounds {[MnIII6FeIII(MeOH)6]Cl3·11MeOH·H2O (1a), [MnIII6FeIII(MeOH)6]Cl3·3MeOH·H2O (1b), and [MnIII6FeIII(MeOH)6](PF6)2(OAc)·11MeOH (3)} and the one‐electron reduced congener [MnIII6FeII(MeOH)4](BPh4)2·3MeOH·toluene (2) are presented. The half‐wave potential of the FeIII/FeII couple in [MnIII6FeIII/II]3+/2+ is E1/2 = –0.06 V versus Fc/Fc+. The overall molecular structures of the complexes resemble those of the already published [MnIII6Mc]3+ compounds (Mc = CrIII, CoIII, MnIII, FeIII). The [MnIII6FeII]2+ dication, however, exhibits shorter Mn–NC≡N bonds than the tricationic [MnIII6Mc]3+ complexes, as well as a higher degree of aromaticity of the central benzene ring of the triplesalen ligand. The electronic absorption spectrum of [MnIII6FeII]2+ differs considerably from the superimposable spectra of tricationic [MnIII6Mc]3+ complexes in exhibiting lower‐energy ligand field transitions due to stronger π‐donation of the surrounding ligands and weaker absorption features in the 27000–35000 cm–1 region, due to a weaker keto‐enamine character of the central phloroglucinol unit. AC susceptibility measurements indicate single‐molecule magnet (SMM) behavior for 1a and 3. Analysis of the DC magnetic data (μeff vs. T, VTVH) of these compounds by a full‐matrix diagonalization of the spin‐Hamiltonian including isotropic exchange, zero‐field splitting with full consideration of the relative orientation of the D‐tensors, and Zeeman interaction reveals JMn,Mn = –1.00 to –1.15 cm–1 (Ĥex = –2JijŜi·Ŝj), JFe,Mn = +0.50 to +0.80 cm–1, and DMn = –3.5 cm–1. These values are similar to those previously found for [MnIII6FeIII][FeIII(CN)6]. For 2, the simulations indicate very weak antiferromagnetic MnIII–MnIII interactions within the trinuclear triplesalen subunits (JMn,Mn(1) = –0.20 cm–1) as well as across the central diamagnetic FeII ion (JMn,Mn(2,cis) = –0.06 cm–1, JMn,Mn(2,trans) = –0.18 cm–1), whereas DMn = –3.5 cm–1. The JMn,Mn(1) coupling in 2 is much less antiferromagnetic than in the tricationic [MnIII6Mc]3+ compounds; this is interpreted in terms of a stronger ferromagnetic contribution to the exchange interaction due to more efficient spin‐polarization through the central benzene ring, the aromatic nature of which is more pronounced.