The family of the cucurbit[n]uril hosts (n = 5-10) has tremendous potential as molecular receptors.  Prepared by the condensation of glycoluril with formaldehyde in acidic media, these macrocyclic compounds are excellent hosts for hydrophobic cations in aqueous media.  In optimum cases they afford unequaled binding affinity and considerable selectivity.  Our group is particularly interested (1) on the properties of cucurbituril complexes of redox active guests, (2) on the use of these fascinating hosts to control the formation of dye J- and H-aggregates and (3) on their applications to the preparation of supramolecular polymers.