The synthesis, cation binding and transmembrane conductive properties of a novel group of synthetic ion channels containing a redox-active centre are described. Experiments using a black lipid membrane preparation revealed that these compounds function effectively as ion channels. Subsequent ²³Na NMR spectroscopy studies focused on a synthesized ion channel with a ferrocene centre. When incorporated in vesicular bilayers, this channel was demonstrated to support a Na⁺ flux that was at least six times faster than ion transport by monensin. Since oxidation of the ferrocene moiety completely inhibited the Na⁺ transport, the redox-active centre provides a potential mechanism for controlling ion flux.