We present two novel UV-vis absorption spectroelectrochemical cells for the study of electrochemical processes at polarized liquid vertical bar liquid interfaces based on the parallel incidence of the light beam with respect to the interface. The first one is a crude design (Cell 1) based on an existing cylindrical cell for liquid vertical bar liquid electrochemistry. The second design (Cell 2) is Superior and based on the assembly of the four-electrode set-up inside a rectangular quartz spectrophotometric cuvette. in both cases it is demonstrated that absorption spectroelectrochemistry in parallel beam configuration can be a sensitive probe of processes such as ion transfer at the polarized liquid vertical bar liquid interface, if the contribution from the bulk of the sampled phase is removed. In particular, the electrochemical and spectroscopic performance of both cell designs was evaluated using the well-known transfer of Ru(bpy)(3)(2+) across the water vertical bar 1,2-DCE interface as a model reaction. (C) 2008 Elsevier Ltd. All rights reserved.