Bilayer consisting of polypyrrole, PPy, as the inner and poly(2,5-dithienyl-(N-3-phosphorylpropyl)pyrrole, p(TPTC3-PO3H2) as the outer layers was electropolymerized in layer-by-layer steps. Due to the presence of phosphonic acid functionality tethered to the backbone of outer polymer, the system is capable of binding organic and inorganic bases and offers an easy and convenient access to sensor devices. The ion transport through the polypyrrole film depends on its thickness. The thin layer of pTPTC3-PO3H2 does not hinder the redox and ion-transport characteristics of the PPy layer. (c) 2005 The Electrochemical Society.