Electrochemical properties of both monomers were tested and compared with those of pristine Py (Figure and S4, Supplementary materials). It occurred that Py-COOH efficiently electropolymerizes under the similar conditions as Py (Figure ). In contrast, Py-NH2 electropolymerization (Figure ) resulted in deposition of non-conducting film and blocking electrode surface (Figure ). Therefore, in further experiments Py-COOH was used.