Angewandte Chemie, Accepted Article.
We report a series of meltable Fe II complexes, which, depending on the length of aliphatic chains, display abrupt “forward” low‐spin to high‐spin transition or unprecedented melting‐triggered “reverse” high‐spin to low‐spin transition on temperature rise. The “reverse spin transition” is perfectly reproducible on thermal cycling and the obtained materials are easily processable in the form of thin film due to soft matter nature. We found that the discovered approach represents a potentially generalizable new avenue to control both the location in temperature and the direction of the spin transition in meltable compounds.