Complexes 2-Ln and 4-Ln were characterized by SQUID magnetometry to determine their electronic structure and the effect of switching the TEMPO -anion to a TEMPO • radical (see SI for full details). Room temperature values of the product of magnetic susceptibility and temperature (χT) for 2-Ln are within the expected ranges for their respective Ln 3+ ions (Table ). The χT values for 2-Ln linearly decrease with decreasing temperature (Figure ) as the ground-term CF states, and low lying HJ and FJ states for 2-Sm, are depopulated. These ground terms are 6 H5/2