For the remaining molecules, their geometry in the CS structures corresponds to a conformer that is energetically far above the gas phase global energy minimum. The structures LIRLIL and LIRLEH each contain a biaryl guest with high ∆E con f , at 22.5 and 21.0 kJ/mol, respectively; both CS structures also contain a second guest with much lower ∆E con f (see Table ). In the gas phase, the global minimum conformer for both BBA-8,12-OMe and BBA-8,10,12-OMe adopts a geometry stabilised by intramolecular hydrogen bonding. The biaryl guests which adopt a local conformation with no intramolecular hydrogen bonds have a high ∆E con f , due to the high energetic barrier for geometric distortion/destabilisation of the molecule. The biaryl guests with low ∆E con f adopt geometries with intramolecular hydrogen bonding intact after relaxation to their local conformation (see Fig. ). Both guest molecules of tenebrathin (COQBIW), as mentioned previously in discussion of ∆E total , also adopt relatively high energy conformers in their CS structure, with ∆E con f =19.98 and 28.45 kJ/mol. Previous work by Thompson showed that conformers with large surface areas are favoured in the crystal structures of flexible molecules, as it provides greater available surface area for stabilising intermolecular interactions, while lower energy conformers typically display relatively compact geometries to enable intramolecular stabilisation. This is what we observe for tenebrathin, which adopts extended conformers in its CS structure, compared to the folded global energy minimum conformer (Fig. ), that could be stabilised by general van der Waals interactions with solvent and the framework. This is not the case for high ∆E con f values in LIRLIL and LIRLEH however, where the driving force for these molecules comes from breaking intramolecular hydrogen bonding stabilised by strong, specific interactions with the framework (Fig. ).