Large separations between ground and excited magnetic states in single‐molecule magnets (SMMs) are desirable to reduce the likelihood of spin reversal in the molecules. Spin‐phonon coupling is a process leading to magnetic relaxation. Both the reversal and coupling, making SMMs lose magnetic moments, are undesirable. However, direct determination of large magnetic states separations (>45 cm−1) is challenging, and few detailed investigations of the spin‐phonon coupling have been conducted. The magnetic separation in [Co(12‐crown‐4)2](I3)2(12‐crown‐4) (1) is determined and its spin‐phonon coupling is probed by inelastic neutron scattering (INS) and far‐IR spectroscopy. INS, using oriented single crystals, shows a magnetic transition at 49.4(1.0) cm−1. Far‐IR reveals that the magnetic transition and nearby phonons are coupled, a rarely observed phenomenon, with spin‐phonon coupling constants of 1.7–2.5 cm−1. The current work spectroscopically determines the ground–excited magnetic states separation in an SMM and quantifies its spin‐phonon coupling, shedding light on the process causing magnetic relaxation.