A series bis-ureas and bis-thioureas appended to a central acridinone scaffold were synthesised, and their chloride binding and transport properties investigated. Compounds 3 and 4 are among the most potent transporters reported by our group to date. Extensive mechanistic studies revealed the transporters function predominantly as HCl cotransporters and diffuse back as deprotonated species or complexes with deprotonated fatty acids due to strong interactions between the phospholipid headgroups and the neutral receptors. The electroneutral HCl transport facilitated by these compounds at low-dose concentrations highlights their potential to disrupt cellular pH gradients and find application as powerful anti-cancer agents.