A supramolecular helicate with two independent Fe(II) switchable centres and a [Fe(anilate) 3 ] 3- guest.

A biphenyl-spaced bis-pyrazolylpyridine ligand interacts with ferrous ions to engender a dimetallic helical coordination cage that encapsulates an Fe tris-anilate complex. The host-guest interaction breaks the symmetry of the Fe centers causing a differential spin crossover behavior in them that can be followed in great detail crystallographically.