Complexes 1-Ln vary in color, with solutions ranging from pale yellow (1-La) to deep purple (1-Sm). To study these electronic transitions further, the UV-Vis-NIR spectra of 2 mM toluene solutions of 1-Ln were recorded at room temperature (compiled in Figure ; see Supporting Information Figures S48-S52 for individual spectra). All spectra exhibited an intense charge transfer (CT) absorption tailing into the visible spectrum from the UV region.