Coordination/metal–organic cages inside out

• Defined coordination cages (CCs) with metal-pyridine coordination bonds. • Defined metal-organic cages (MOCs) bearing tetracarboxylates paddlewheel complexes. • Meta-analyzed experimental information of 197 CCs and 83 MOCs. • Unveiled roles of ligand, metal ion, temperature and solvent for cage formation. • Discussed challenges and future perspectives of CCs and MOCs in unexplored areas. Cage-like molecules, assembled by the coordination of multiple metal ions and organic links, are pushing new frontiers in science due to their design flexibility and the resulting diverse and unique chemical properties. This field has been advanced by two close but distinct chemistry communities. Consequently, the family of molecules referred to as coordination cages (CCs) constituted of metal-pyridine coordination bonds or metal–organic cages (MOCs) based on dinuclear tetracarboxylates paddlewheel complexes in each community had not been reviewed cross-sectionally, even though they are conceptually similar. This review article extracted and compared experimental information on a total of 197 CCs and 83 MOCs from 185 reports to identify their synthetic and structural signatures. We did not merely enumerate the reports we collected; we meta-analyzed the data extracted from the reports and highlighted both the similarities and dissimilarities between CCs and MOCs. As a result, we clarified the key parameters governing the synthetic conditions. Furthermore, we identified a new research direction by visualizing unexplored features and properties of CCs and MOCs. This review article provides a good tutorial both for researchers attempting to cross the boundary between CCs and MOCs and those who are new to the field.