A hybrid bilayer membrane (HBM) has been prepared on a glassy carbon electrode (GCE) The HBM consists of an inner layer of n-hexadecylamine (HDA) covalently attached at the GCE and an out-layer of tetra-(N-hexadecylpyridiniurnyl)porphyrin (TC16PyP). The HDA was covalently bounded on the carbon surfaces through its primary amine under cyclic voltammetric potential scans forming a self-assembled monolayer (SAM). The TC16PyP forms a second layer on top of the HDA layer due to hydrophobic interaction. The TC16PyP/HDA/GCE assembly has been utilized to study ion transport through hybrid bilayer membranes. The ion transport through this porphyrin-terminated HBM has been found to strongly dependent on pH. It allows negatively charged redox ions, Fe(CN)(6)(3-), to penetrate at pH <6 while repelling positively charged Ru(NH3)(6)(3+). However, no faradaic current has been detected at pH >6 with either ions. We believe that electrostatic interaction between the redox ions and the charged membrane is the main reason for this pH dependent ion transport. (C) 2010 Elsevier Ltd. All rights reserved.