We recently reported that H-bond donor groups, which are not involved in the binding of the anion, strongly inhibit the anion transport ac7vity. For instance, while o-phenylenebisureas are highly ac7ve anion transporters, 38 the corresponding m-phenylenebisureas showed hardly any transport ac7vity. This was aYributed to the interac7on of the second anion binding site with the phospholipid headgroups, ac7ng as an anchor and preven7ng transport. Based on this finding, we hypothesised that symmetric azine TT would be poor anion transporter. On the other hand, combining T with the simple 4-methylbenzaldehyde A would yield azine TA, that we expected to be ac7ve as an anion transporter. We also tested 4-hydroxybenzaldehyde B as modulator, predic7ng that the resul7ng compound, TB with an addi7onal H-bond donor, would likely exhibit poorer transport ac7vity due to increased interac7ons with the lipid headgroups and water.