This paper presents an easy, efficient and reproducible way to obtain cobalt polyporphine films. A fast three step process (less than one hour) based on electrosynthesis of magnesium polyporphine of type I followed by a demetallation in acid medium and then cobalt insertion inside the porphine units allowed us to obtain an interesting material with a high density of active cobalt(II) centers. Kinetics studies were conducted to determine the best conditions for the demetallation and remetallation steps. Moreover, IRATR and UV-visible measurements attested that the initial molecular structure of the porphine units was kept during the three step process. Qualitative composition of polyporphine films has been confirmed via XPS and EDX methods. In situ specific conductivity of these polyporphine polymers of type I has been determined as a function of the imposed potential, i.e. of the oxidation degree. (C) 2016 Elsevier Ltd. All rights reserved.