In 2017, Aromí, and co-workers reported SCO in a luminescent dinuclear iron complex coordinated with a bis(pyrazolylpyridyl) ligand that contains a central photochromic dithienylethene spacer . The iron complex [Fe2(L15)3](ClO4)4 ( photo-conversion between the LS to the photo-excited metastable HS state (7%) with a TLIESST value of ca. 80 K. Although complex 21 exhibited reversible photo-switchable PL properties in solution due to photo-conversation of diarylethene ligand, no synergic relation between SCO and luminescence was observed (Fig. ).