Potentiometric selectivities show that in fluorous ion-selective electrode membranes the tetrabutylammonium ion binds to fluorophilic proton ionophores. For the ionophore bis[3-(perfluorooctyppropyl] (2,2,2-trifluoroethyl)-amine, this type of interaction is confirmed by the effect of the ionophore on the ionic conductivity of perfluoro(perhydrophenanthrene) solutions of a fluorophilic NBu4+ salt. In this system, ion pairs, triple ions, and higher ionic aggregates dominate over single ions, and the ionophore increases the conductivity by favoring the formation of ion aggregates with a net charge. These observations are consistent with the formation of R3N+-C(R)-H center dot center dot center dot NR3 type hydrogen bonds between the nitrogen atom of the ionophore and the hydrogen atoms in the a position to the positively charged quaternary ammonium center of NBu4+. Similar interactions were observed in a number of crystalline phases. To date, observations of C-H center dot center dot center dot N type hydrogen bonds in liquid phases have been very few, and solution phase N+-C-H center dot center dot center dot N type hydrogen bonds have not been reported previously. Interestingly, no interactions between NBu4+ and the more basic ionophore tridodecylamine were observed in conventional plasticized poly(vinyl chloride) membranes doped with the ionophore tridodecylamine, emphasizing the uniquely low polarity of fluorous phases.