LiCl (99%, Merck), tetramethylammonium (TMA) chloride (≥ 99%, Fluka), 1,2-dichloroethane (DCE) (pure p.a., Chempur), ,,-trifluorotoluene (TFT) (anhydrous ≥ 99%, Merck) and diphenyl ether (Merck). Organoboron compounds (OBC) including arylboronic acids (2-6, 8) , oxaboroles (10-14) , cyclic borinic acids, namely dibenzoborinines (15-17) and triarylborane 18 were available from our previous studies. Phenylboronic acid (1) was purchased from Merck. 1,3,5-Phenylenetriboronic acid (7) and benzoxaborole (9) were synthesised according to the known literature procedures. 1 H, B, and C NMR spectra were recorded on Agilent NMR 400 MHz DDR2 spectrometers. H and C chemical shifts were referenced to TMS using known chemical shifts of solvent residual peaks. (19). A solution of diphenyl ether (1.70 g, 0.010 mol) in 5 ml THF was added dropwise to a stirred solution of n-BuLi (2.5 M in hexane, 8.4 ml, 0.021 mol) in 40 ml THF at -78 °C. The mixture was warmed slowly to 0 °C and stirred for 4 h. The mixture was cooled to -78 °C and B(OMe)3 (0.56 mL, 0.005 mol) was added. The cooling bath was removed, the mixture was warmed to room temperature and stirred for additional 2 hrs. Then, the reaction was quenched with 2 M HCl to reach pH = 5. The aqueous phase was separated and extracted with Et2O (2 × 10 mL). The extracts were added to the organic phase, dried over magnesium sulfate and concentrated under reduced pressure. The obtained solid was washed with hexane (2 × 10 ml) and dried in vacuo to give crude product. Product was purified with column chromatography using toluene as eluent. Resulted solution was concentrated in vacuo to give 19 as white solid (0.78 g, yield = 45 %). H NMR (400 MHz, CDCl3) δ = 7.99 (dd, J = 7.6, 1.8 Hz, 2H), 7.71 (ddd, J = 8.7, 6.9, 1.8 Hz, 2H), 7.54 (d, J = 8.4 Hz, 2H), 7.50 -7.43 (m, 2H), 7.32 -7.23 (m, 3H), 7.12 (d, J = 8.1 Hz, 1H), 7.03 (t, J = 7.9 Hz, 2H), 6.83 (t, J = 7.5 Hz, 1H), 6.76 (d, J = 7.7 Hz, 2H) ppm. C{ 1 H} NMR spectra, the resonances of boron-bound carbon atoms were not observed as a result of their broadening by the quadrupolar boron nucleus. Water was filtered and demineralized with an ELIX system (Milipore). The electrolyte salt of the organic phase, bis(triphenylphosphoranylidene)-ammonium tetrakis(4-chlorophenylborate) (BTPPATPBCl), was prepared by methathesis of bis(triphenylphosphoranlidene)ammonium chloride (BTPPACl) and potassium tetrakis(4-chlorophenyl)borate (KTPBCl), following the procedure described elsewhere . Both components were purchased from Merck. Electrochemical measurements Cyclic voltammetry (CV), differential potential voltammetry (DPV) and square wave voltammetry (SWV) were performed with an Autolab potentiostat (Metrohm Autolab B.V., Netherlands) controlled by the NOVA software (version 2.1.2). Parameters for DPV were as follows: step potential 0.005 V, modulation amplitude 0.025 V, modulation time 0.05, interval time 0.5. Parameters for CV measurements were: scan rate 0.01 V/s, step 0,002 V. All measurements were performed in a fourelectrode system with two platinum electrodes and two silver-silver chloride pseudoreference electrodes. The Ag/AgCl electrodes were prepared by immersing an Ag wire in a saturated solution of FeCl3 overnight and later sonicated in ultrapure water to remove the FeCl3. Fabrication of electrochemical cells The standard electrochemical cell was custom-made by a glassblower. The counter electrodes were made of two Pt wires embedded directly in the glass vessel with the interface positioned between them. The pseudoreference Ag/AgCl wires were immersed in aqueous solutions, one in the aqueous phase and the other in a reference solution in contact with the organic phase. The miniaturized electrochemical cell was prepared using a glass spectrophotometric cuvette with a 2  10 mm cross-section. The capillary for the reference solution was bent from the Pasteur pipette tip in Figure Photograph of the standard (left) and miniaturized (right) cell for electrochemistry at the liquidliquid interface. In the case of miniaturized cell the counter electrode from the organic phase passes through the aqueous phase and therefore needs to be insulated in glass, all the other parts of the cell correspond the macroscopic design. a flame. One of the Pt wires was positioned in the organic solution. It was partially covered with glass to isolate it from the top aqueous solution. A plastic clip held together the two counter electrodes to provide a constant distance between them during subsequent measurements. The general scheme of the applied measuring system was the same as in a standard electrochemical cell. Pictures of both cells are provided in Figure .