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A brownish-black complex [Fe^III(L)₂] (1) (S = 0), supported by two tridentate redox-active azo-appended o-amidophenolates [H₂L = 2-(2-phenylazo)-anilino-4,6-di-tert-butylphenol], has been synthesized and structurally characterized. In CH₂Cl₂ 1 displays two oxidative and two reductive 1e^– redox processes at E_1/2 values of 0.48 and 1.06 V and −0.42 and −1.48 V vs SCE, respectively. The one-electron oxidized form [1]⁺ isolated as a green solid [Fe^III(L)₂][BF₄] (2) (S = 1/2) has been structurally characterized. Isolation of a dark ink-blue one-electron reduced form [1]⁻ has also been achieved [Co^III(η⁵-C₁₀H₁₅)₂][Fe^III(L)₂] (3) (S = 1/2). Mössbauer spectral parameters unequivocally establish that 1 is a low-spin (LS) Fe^III complex. Careful analysis of Mössbauer spectral data of 2 and 3 at 200 and 80 K reveal that each complex has a major LS Fe^III and a minor LS Fe^II component (redox isomers): [Fe^III{(L^ISQ)^−•}₂ …