Pentacoordinate Fe(III) complexes [Fe(L-MeO) X-2] and [Fe(L-EtO)(2)X], X = Cl and Br, show the slow magnetic relaxation that is enhanced by the applied static magnetic field. A substitution of the distant ethoxy group to the methoxy group residing at the phenyl ring of a Schiff base N,O-donor ligand (L-MeO vs L-EtO) considerably influences the relaxation characteristics. In the chlorido complex [Fe(L-MeO)(2)Cl], the following three slow relaxation channels are recognized as possessing different relaxation times: tau(LF) = 0.47 s, tau(IF) = 13 ms, and tau(HE) = 26 mu s at the static field B-DC = 0.2 T and T = 1.9 K. In the bromido complex [Fe(L-MeO)(2)Br], only the following two relaxation channels are seen: tau(LF) = 0.30 ms and tau(HF) = 139 mu s at B-DC = 0.15 T and T = 1.9 K Due to D > 0, the Orbach relaxation mechanism does not apply, and the temperature dependence of the high-frequency relaxation time can be described by two Raman-like terms.