The Yb 3+ emission spectra of O,Oʹ-coordinated 1-Yb and 3-YbEu or [Yb(Tp)2(hfac)] (Figure ) each exhibit two maxima, one of which has significantly greater intensity (max = 975 (intense), 1030 nm). In contrast, 3-DyYb gives three emission maxima, each of similar intensity (max = 975, 1005, 1030 nm, ESI Figure ). We attribute this change in profile to the greater ligand field effect experienced by Yb(hfac)3 in the N,Nʹ diimine site of pd when compared to [Yb(Tp)2] + in the O,Oʹ site, which alters the Stark splitting of Yb 3+ excited state sublevels. These differences are only possible with selective coordination of Yb 3+ to either the O,Oʹ or the N,Nʹ binding site. Notably, three emission maxima of similar intensities were also observed from [Yb(hfac)3(N,Nʹpd 0 )]. To understand the differences in excitation patterns between 3-YbEu and 3-DyYb, it is informative to consider the possible ET pathways as shown in Figure . Excitation of the hfac ligands (Ex = 317 nm) always results in emission from the lanthanide coordinated to hfac, bound in the N,Nʹ binding site of the pd ligand (pathway I in Figure and 5b), as well as ET to the Ln 3+ bound in the O,Oʹ binding site.