The separation of rare-earth ions from one another is challenging due to their chemical and physical similarities. Nearly all rare-earth separations rely upon small changes in ionic radii to direct speciation or reactivity.H erein, we show that the intrinsic magnetic properties of the rare-earth ions impact the separations of light/heavy and selected heavy/heavy binary mixtures.U sing TriNOx 3À ([{(2-t BuNO)-C 6 H 4 CH 2 } 3 N] 3À )r are-earth complexes,w ee fficiently and selectively crystallized heavy rare earths (Tb-Yb) from amixture with light rare earths (La and Nd) in the presence of an external Fe 14 Nd 2 Bm agnet, concomitant with the introduction of ac oncentration gradient (decrease in temperature). The optimal separation was observed for an equimolar mixture of La:Dy,which gave an enrichment factor of EF La:Dy = 297 AE 31 for the solid fraction, compared to EF La:Dy = 159 AE 22 in the absence of the field, and achieving a99.7 %pure Dy sample in one step.T hese results indicate that the application of am agnetic field can improve performance in am olecular separation system for paramagnetic rare-earth cations.