A mononuclear nonheme iron(V)-imido complex, earing a tetraamido macrocyclic ligand (TAML), [Fe-V(NTs)(TAIVIL)](-) (1), was oxidized by one-electron oxidants, affording formation,of an iron(V)-imido TAML cation radical species; [Fe-V(NTs)(TAML(+.))] (2); 2 is a diamagnetic (S = 0) complex, resulting froni the antiferroinagnetic coupling of the low-spin iron(V) ion (S = 1/2) with the one-electron oxidized ligand (TAML(+)). 2 is a competent oxidant in C-H bond functionalization and riltrene transfer reaction, showing that the reactivity of 2 is greater than that of 1.