Molecular perovskites, perovskites of composition AMX 3 where at least one of A, M or X is molecular, have additional degrees of freedom which can produce orderings impossible in atomic perovskites. These new orderings provide novel routes for materials to respond to external stimuli. One area of particular interest is using the molecular components to create electrical polarisation, without the need for the second-order Jahn-Teller distortions or stereoactive lone pairs that drive piezo-and ferroelectricity in atomic perovskites, e.g. BaTiO 3 or Pb(Zr, Ti)O 3 . 2 Molecular perovskites now possess polarisations and transition temperatures which approach those of inorganic perovskites. However, their polarity is typically produced by the orientational order of polar A-site cations. The functionality often bestowed by the MX 3 framework, e.g. ferromagnetism or ferroelasticity, therefore usually couples weakly to the polarisation, limiting the scope for multiferroicity.