Metallosupramolecular squares: from structure to function.

Metallosupramolecular squares have been successfully evolved over the past years as versatile substitutes of the conventional organic macrocycles owing to the development of reliable synthetic protocols and abundant structural variability (metals and ligands). In this review we have presented the fundamental aspects of metallosupramolecular squares such as the strategies for their construction (self-assembly vs. kinetically controlled macrocyclization) and characterization. The major emphasis of this tutorial review lies on the function of metallosupramolecular squares. Thus, the introduction of functionality into these systems has been discussed in detail by highlighting the recent progress toward application in various fields, including molecular recognition, enantioselective sensing, photoluminescence, redox activity and electrochemical sensing, and homogeneous catalysis.