The miniaturized electrochemical cell was used for screening potential ionophores. The ideal ionophore should be sufficiently hydrophobic to minimalize its leaching out of the ion-selective membrane and the organic phase of the ITIES setup. It should also dissolve in any of the commonly used organic solvents immiscible with water. Thus, in the first step the solubility of studied organoboron compounds in DCE and TFT was checked. 10 of the 19 tested compounds dissolved in DCE and 3 in TFT giving in summary 10 compounds that could be tested at least in one of the solvents. Molecular structures of the organoboron compounds are provided in Figure .