Thus, the addition of 5FSQC6 (or CF3SQC6) as an ionophore to the organic phase is not accompanied by anion transfer from the aqueous to the organic phase (Fig. , for 5FSQC6). Instead, the DMFc + ion is likely expelled into the aqueous solution. Nevertheless, we showed that these squaramide-based compounds can be oxidized in the organic phase (see SI), so we investigated the possibility of using the ion receptor itself as a redox probe in the droplet system (Fig 1 . and Fig. . for CF3SQC6).