Light-induced excited spin state trapping (LIESST) has largely been limited to iron complexes and typically requires cryogenic temperatures or large nuclear rearrangements, limiting practical photomagnetic switching. Now a carbene manganese(II) complex achieves LIESST at 141 K in solution, demonstrating that increased metal–ligand covalency and rigidity can stabilize long-lived high-spin states and extend photomagnetic switching towards more practical temperature regimes.