Rigid rectangular, triangular, and prismatic supramolecular assemblies, cyclobis[(2,9-bis[trans-Pt(PEt(3))(2)(PF(6))]anthracene)(4,4'-dipyridyl)], cyclotris[(2,9-bis[trans-Pt(PEt(3))(2)(PF(6))]phenanthrene)(4,4'-dipyridyl)], and cyclotris[bis[cis-Pt(PEt(3))(2)(CF(3)SO(3))(2)]tetrakis(4-pyridyl)cyclobutadienecyclopentadienylcobalt(I)], respectively, based on dipyridyl ligands and square planar platinum coordination, have been investigated by ion mobility spectrometry-mass spectrometry (IMS-MS). Electrospray ionization-quadrupole and time-of-flight spectra have been obtained and fragmentation pathways assigned. Ion mobility studies give cross sections that compare very well with cross sections of the supramolecular rectangle and triangle species on the basis of X-ray bond distances. For the larger prism structures, agreement of experimental and calculated cross sections from molecular modeling is very good, indicating IMS-MS methods can be used to characterize complex self-assembled structures where X-ray or other spectroscopic structures are not available.