Macrocycles 1-3 have four NH H-bond donating groups at the same positions in the macrocycles. However, the groups of these three macrocycles vary from acylhydrazones to (N-alkoxy)amides, which could potentially lead to differences in binding between the three macrocycles. To try and gauge the influence of these Hbond donors on anion affinity, both literature data on anion binding of these functional groups as well as their estimated pKa were considered (see SI for details). It appears that the available anion binding data as well as the pKa values of the moieties in question are not too different and thus not likely to be the main source of observed differences.