omega-(N-Pyrrolyl) alkanethiols with various alkyl chain lengths were prepared to study the formation of self-assembled monolayers (SAMs) bearing a bulky headgroup and the electrochemical deposition of polypyrrole over SAM-modified gold electrodes. Polarized IR reflection-absorption, ellipsometry, and quartz crystal microbalance data showed that an alkanethiol with a longer alkyl chain is better with regard to coverage and ordering of the SAMs. The monolayer coverages are 62%, 74%, 78%, and 78% for omega-(N-pyrrolyl) propanethiol, omega-(N-pyrrolyl) hexanethiol, omega-(N-pyrrolyl) nonanethiol, and omega-(N-pyrrolyl) dode-canethiol, respectively. Due to oxidative desorption of the monolayer, the cyclic voltammograms (CVs) of the SAMs of omega-(N-pyrrolyl) alkanethiols on Au in 0.1 M KCl/H2O display an irreversible oxidation wave at ca. 1.2 eV versus a Ag/AgCl electrode. No redox reaction of the SAM was observed when the CV measurements were carried out in acetonitrile, using Et4NBF4 as an electrolyte. There is also no voltammetric evidence for polymerization of the surface-confined pyrrole units at the potential cyclically scanned from 0 to +1.4 V. The electrochemical deposition of polypyrrole potentiodynamically over monolayers of omega-(N-pyrrolyl) alkanethiols shows that the polymerization potential of pyrrole over long alkyl chain (omega-(N-pyrrolyl) alkanethiol modified gold electrodes was higher than that over short alkyl chain modified electrodes in KCl/H2O. The polymerization of pyrrole apparently occurred without monolayer oxidation. In Et-4-NBF4/CH3CN, SAMs of omega-(N-pyrrolyl) alkaniethiols were stable under a potential scan. During the growth of polypyrrole, the pyrrole molecules in omega-(N-pyrrolyl) alkanethiols may serve as nucleation sites for the growth of polypyrrole. Therefore, polypyrrole films electrochemically deposited on omega-(N-pyrrolyl) alkanethiol monolayers have a denser morphological packing and good adhesion. The conductivity of these films is enhanced as a consequence of the change in morphology.