Self-assembly of 1,3-di(4'-terpyridinyl)arenes by using the labile tpy-Cd(II)-tpy (where tpy = 2,2':6',2 ''-terpyridine) connectivity afforded access to hexacadmium macrocycles in high yield. These supramolecular assemblies were characterized by traveling wave ion mobility mass spectrometry (TWIM-MS).