This article describes the elaboration and characterization of diethylphosphonate‐containing polymers coated electrodes as sensors for the detection of heavy metals traces, by electrochemical impedance spectroscopy. Diethylphosphonate groups were chosen as heavy metals binding sites. Two different series of polymers bearing these anchoring groups were synthesized. Whereas the diethylphosphonate groups are directly incorporated in the aromatic macromolecular chain in some polymers, an aliphatic spacer is removing the chelating site from the polymer backbone in others. The influence of the macromolecular structure on the sensing response was studied, especially for the detection of Pb 2+ , Ni 2+ , Cd 2+ and Hg 2+ . Polymer P6, including the higher amount of diethylphosphonate groups removed from the polymer chain by a short alkyl spacer gave the higher sensitivity of detection of lead ions, with a detection limit of 50 pM.