The perfluoro macrocycles perfluoro-18-crown-6, perfluoro-12-crown-4, perfluoro-15-crown-5, perfluorocyclohexano-15-crown-5, perfluorodicyclohexano-18-crown-6, perfluorodicyclohexano-24-crown-8, and perfluoro-4,7,13,16,21,24-hexaoxa-1,10-diazabicyclo[8.8.8]hexacosane(perfluorocryptand[222]) have been prepared by carefully controlled elemental fluorination. Although they are much weaker bases than their hydrocarbon analogues, these perfluoromacrocycles are very stable materials which should have a number of applications. The crystal structures of perfluoro-18-crown-6 and of a perfluorodicyclohexano-18-crown-6 isomer are reported. Gas-phase studies with several perfluoro crown ethers and with the perfluorocryptand [222] have shown that such macrocycles tenaciously bind O-2(-) and F-. Perfluoro crown ethers and cryptands coordinate anions preferentially over cations. The collisionally activated mass spectra of several perfluoro macrocyclic ions are described.