In this work, we have prepared a perchlorate sensor based on cobalt phthalocyanine derivative molecules. The membrane was deposited onto gold substrates using dip-coating method. Adhesion and morphological properties have been studied using contact angle measurements. Then, the sensitivity, the detection range and the detection limit were determined using electrochemical impedance spectroscopy (EIS) measurements. The sensor was also studied specificity towards interfering ions nitrate (NO3-), carbonate (CO32-) and sulfate (SO42-) to show the specificity of the membrane. The impedance behavior of the perchlorate sensor (gold/membrane) has been modeled by an equivalent electrical circuit using a modified Randles model for better understanding the phenomena present at the interface membrane/electrolyte.