Cobaltabisdicarbollide-doped polypyrrole (PPy-[Co(C2B 9H11)2]) nanostructures have been produced by directed, potentiostatic electropolymerization using a patterned combination of conducting and insulating thiols (4-aminothiophenol and octadecylmercaptan, respectively). The different conducting characters of both self-assembled monolayers guides the PPy-[Co(C2B9H11) 2] deposition over the pattern. In this way we have produced doped, nanostructured annular polypyrrole rings, ∼400 nm high and ∼200 nm wide at full width-half maximum height. Two processes are thought to affect the polypyrrole growth; primarily, the different conducting characters of the self-assembled thiol monolayers, but also the hydrophobic interactions between the electrolyte and the self-assembled monolayer. The effects of the hydrophobicity of the doping anion were also studied by comparing the microstructures obtained for polypyrrole doped with the lipophilic [Co(C 2B9H11)2]- anion and those doped with hydrophilic Cl- and ClO4- anions. © IOP Publishing Ltd.