A dinuclear iron(II) complex, [(TPyA)FeII(THBQ(2-))FeII(TPyA)](BF4)2 [TPyA = tris(2-pyridylmethyl)amine; THBQ(2-) = 2,3,5,6-tetrahydroxy-1,4-benzoquinonate] exhibiting both spin crossover with hysteresis and ferromagnetic exchange

Dinuclear [(TPyA)FeII(THBQ(2-))FeII(TPyA)](BF4)2 (1) possesses hydrogen bonding interactions that form a 1-D chain, and pi-pi interactions between the 1-D chains that give rise to a 2-D supramolecular-layered structure, inducing hysteresis in the spin crossover behavior; 1 has shown spin crossover behavior around 250 K with thermal hysteresis and ferromagnetic interactions at low temperature.