A novel class of cyclic polyoxyethylene derivatives incorporating a polybenzylated oxane system has been prepared via ruthenium‐catalyzed ring‐closing metathesis. These polyethers were incorporated into phospholipid vesicles and shown to facilitate transmembrane sodium transport. Maximum efficiency in sodium flux occurred when polyoxygenated chain lengths were similar to the leaflet thickness in bilayers. It is proposed that polyethers dimerize in order to function. The association constants of these polyethers with alkali metal cations and methyl ammonium ion have been evaluated using Cram's picrate extraction method.