The discovery of transmembrane anion transporters continues apace driven by the potential application of these compounds in the treatment of diseases such as cancer 2 and cystic fibrosis. A successful strategy to design anionophores is to append hydrogen bond donor groups to a lipophilic scaffold. Examples include cholapods, ortho-phenylenes, trans-decalins, and anthracenes. We have previously shown that there is an optimal log P for each class of anion transporter. Compounds with a low log P value may not be able to efficiently partition into a lipid bilayer whilst compounds with a high log P may not be deliverable and instead need to be pre-incorporated into a lipid bilayer to study their transport properties. We therefore decided to investigate the use of acridinone as a scaffold for a bis-urea and thiourea-based anion transporters. Acridinones are aromatic heterocyclic compounds that exhibit distinct optical properties, resulting from strong absorption and emission in the UV-vis region. These compounds (1-10) possess a potential additional hydrogen bond donor (as with carbazole bis-ureas) from the acridinone NH group whilst the lipophilicity of the compounds is attenuated by the heteroatoms relative to analogous acridine-based compounds (Figure ). We have previously studied acridinones as anion receptors and sensors. Compounds 1 and 6 were found to interact with chloride. Perturbations in the chemical shifts attributed to the (thio)urea protons were fit to a 1:1 receptor:anion binding model and chloride binding constants were determined to be Ka = 273 M -1 and Ka = 53 M -1 for the bis-urea (1) and bis-thiourea (6), respectively. In this study we prepared a larger series of bisureas and thio-ureas and studied their anion transport properties in phospholipid bilayer membranes. Please do not adjust margins