Cyanide‐Bridged Molecular Squares – The Building Units of Prussian Blue

Cyanide‐bridged molecular squares offer a unique opportunity for study, as they represent a model of the simplest unit of Prussian blue and allow access to a wide range of physical properties that can be monitored, such as rich electrochemistry, valence‐ and spin‐state control, and spin‐crossover phenomena. This microreview presents recent findings in the field of cyanide squares with particular focus on their syntheses and physical properties.