Simultaneous Photo‐Induced Magnetic and Dielectric Switching in an Iron(II)‐Based Spin‐Crossover Hofmann‐Type Metal‐Organic Framework

Abstract Molecular materials possessing photo‐tunable polarization switching is promising for optical switches, smart sensors, and data storage devices. However, it is challenging to devise a molecular material featuring simultaneous switchable magnetic and dielectric properties with regard to non‐invasive and convenient light stimulus. Herein, we report a new Hofmann‐type metal–organic framework (MOF) {Fe(bpt)[Pt(CN) 4 ]} ⋅ 0.5anth ( 1 , bpt=2,5‐bis(4‐pyridyl)thiophen; anth=anthracene), which displays thermo‐ and photo‐switchable magnetic and dielectric properties. Photo‐monitored structural analyses revealed that it was the photo‐induced deformation of Fe II coordination sphere and relative movement of guest anthracene that resulted in the variation of the local electric dipoles. These findings provide a new strategy to realize polarization switching through the light‐induced spin crossover, and would be of fundamental significance for future photo‐switchable and multifunctional materials.