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We present a family of trigonal pyramidal iron(II) complexes supported by tris(pyrrolyl-α-methyl)amine ligands of the general formula [M(solv)_n][(tpa^R)Fe] (M = Na, R = tert-butyl (1), phenyl (4); M = K, R = mesityl (2), 2,4,6-triisopropylphenyl (3), 2,6-difluorophenyl (5)) and their characterization by X-ray crystallography, Mössbauer spectroscopy, and high-field EPR spectroscopy. Expanding on the discovery of slow magnetic relaxation in the recently reported mesityl derivative 2, this homologous series of high-spin iron(II) complexes enables an initial probe of how the ligand field influences the static and dynamic magnetic behavior. Magnetization experiments reveal large, uniaxial zero-field splitting parameters of D = −48, −44, −30, −26, and −6.2 cm⁻¹ for 1−5, respectively, demonstrating that the strength of axial magnetic anisotropy scales with increasing ligand field strength at the iron(II) center. In the case of 2,6 …