Understanding magnetic exchange interactions is critical for the design of single-molecule magnets (SMMs). Singh et al. employed wave-function-based methods and DFT calculations to investigate the magnetic properties of Ln2@C79N (Ln = Gd, Dy) molecules (Figure ), predicting record-high magnetic exchange interactions and a substantial barrier for magnetization reversal. Their computational results revealed an unprecedented ferromagnetic exchange interaction of approximately 200 cm -1 between the Gd(III) ions and the radical nitrogen-doped fullerene cage, an order of magnitude larger than previously reported radicallanthanide interactions. For the anisotropic Dy2@C79N system, calculations revealed that the strong Dy-radical exchange significantly suppresses quantum tunneling of magnetization (QTM), a key limitation in SMM performance. The computed magnetization blockade barrier exceeded 580 cm -1 , a value among the highest reported at the time. This enhancement arises from direct exchange coupling and charge transfer from the fullerene cage to the lanthanide ions. Subsequent experimental studies confirmed these predictions. High-frequency electron paramagnetic resonance (HF-EPR) measurements on Gd2@C79N established a ferromagnetic ground state with a total spin of S = 15/2, which agrees with theoretical predictions. The estimated exchange constant (~170 cm -1 ) closely matched computational results. Additionally, magnetization studies on Dy2@C79N demonstrated that the strong Dy-radical exchange