The electrochemiluminescence (ECL) of perylene (PE) has been studied by the electrochemical measurements involving a new transfer function in the frequency domain. When the sufficient voltage is imposed between two platinum electrodes in acetonitrile containing PE, the cation radical PE+ and anion radical PE- are formed on the anodic and cathodic electrodes, respectively, and the reaction of PE+ with PE- emits the fluorescence. This luminescence was measured by a chemiluminescence detecter combined with the electrochemical cell for the flow injection analysis. The ECL impedance, which is the ratio of the luminescence amplitude to the current, was determined by the frequency response analyzer. The ECL impedance shows the frequency dispersion because the ECL has an induction period due to the diffusion process after the electrolysis. The ECL mechanism was discussed by comparing the experimental results of ECL impedance with the theoretical equations. (C) 2004 Elsevier B.V. All rights reserved.