Cram and co-workers reported the synthesis of resorcinarene-derived macrocyclic cavitands with extended aromatic units. These were able to adopt conformations referred to as vase, 174 in which the aryl arms are axial, i.e. perpendicular to the plane of the resorcinarene base, and kite, in which the arms splay outwards in an equatorial fashion (Fig. ). By introducing substituents (e.g. methyl group) onto the 2-position of the resorcinol components (X in Fig. ), the structures could be locked into the kite conformation. The kite conformers provided a suitable π-surface for dimerisation, observed in the solid-state by SCXRD analysis, 175 and in solution by vapour pressure osmometry and NMR in CDCl3 (e.g. evidenced by shielding of methyl groups directed internally in the dimer). 176 Such capsule-type dimers were termed velcraplexes.