The electron-deficient cavity of HCs enables encapsulation of suitably sized anionic guests. Efficient anion recognition has been reported for bambusurils, heterobambusurils, 52 biotinurils, and cycHCs. 11 We were fortunate to obtain single crystals of the PF 6 -inclusion complex with (-)-mixHC [8] (Figure , S59-S65). DFT modelling study of mixHC [8] diastereomers (S66-S78) revealed clear differences in their conformations (Figure ). The cavity, which is mainly surrounded by CU units, is mostly distorted by biotin position. Therefore, its influence on the anion binding properties was evaluated via comparison of the three HC [8] hosts. Encapsulation of the selected anions by the new mixHC [8]s was studied by ITC (Figure , Table , Figures ); the data for cycHC [8] was available from previous work. 11 Complexation between the mono-biotinylated macrocycles and selected chaotropic anions (ClO 4 ˉ , PF 6 ˉ and SbF 6 ˉ) in methanol and a methanol-water mixture (1:1) occurred as an exothermic enthalpy-driven process. The association constants for PF 6 ˉ were greater than that of ClO 4 ˉ in both media, which explains the better templating properties of PF 6 ˉ. Noticeably, the differences between the affinities of the three HC [8] derivatives are the smallest for templating PF 6 ˉ anion, while for ClO 4 ˉ and SbF 6 ˉ either (+)-mixHC [8] or cycHC [8], respectively, exhibit stronger binding. The noted dissimilarities highlight distinctions in the cavities and steric accessibility of these host compounds with potential in a diverse array of applications with unique guest-binding properties.