3D Au-Ag heterometallic supramolecular cage: Triplet capture by heavy atom effect

► A 3D heterometallic Au/Ag molecular cage has been synthesized by self-assembly reaction. ► Empty inner cavity has been used in molecular recognition processes. ► Large number of heavy metal atoms induces triplet population of organic molecules. ► 3D cage induces the observation of phosphorescence emission of small aromatic molecules. ► Supramolecular π-acid-base stacks are produced between metallic cage and organic molecules.