The electrochemical and spectroelectrochemical behavior of 9‐substituted with CN and COOH acridine N‐oxides with potential antitumor activity was investigated. In SER spectra of the investigated compounds, the ring stretching vibration at 1568 cm−1 for 9‐CN‐substituted compound respectively 1639 cm−1 for 9‐COOH‐substituted compound was analyzed. Cyclic voltammograms indicates that the reduction potential −0.766 V for CN substituted compound increase towards −0.745 V for COOH substituted compound. The proposed theoretical method in the electrochemical impedance spectroscopy uses a reference redox dielectrode and a multielectrode containing the compound. To account for the change of electrochemical impedance we have considered two theoretical quantities: a pseudocapacitance and a pseudo inductance. Two possible arrangements of them: in series, respective in parallel can be used like criteria of drug classification.