AbstractThe title compounds (1 and 3, respectively) were studied by X‐ray crystal structure analysis. Both are trigonal, space group R3, with lattice parametersa= 27.718(6),c= 8.161(2) Å,Z= 3 anda= 31.267(7),c= 6.560(2),Z= 18, respectively. The dodecamethyl compound 1 is isomorphous with its parent hexakis(4‐benzylphenoxy)benzene (2), a known host. However, ‘collapse’ along thec‐axial direction has occurred such that the appreciable clathrate cavity of 2 has been replaced by only a very small residual void for 1. Phenol 3 does not pack in discrete [OH]6hydrogenbonded hexamers; instead, molecules are assembled in infinite chains, linked by OH…︁O hydrogen bonds of length 2.735(3) Å, which are propagated along threefold screw axes. A variable‐temperature CPMAS NMR study of sidechain aryl group rotation in 1 gives a value ΔG≠of 14.0 ± 0.7 kcal mol−1(at 42 °C) for the (crystallographically unique)para‐disubstituted ring, a similar 14 kcal mol−1free energy barrier being found hindering rotation of this ring, and of the ou