Using a two-dimensional electrogenerated chemiluminescence (ECL) observation system with a CCD detector, the dynamic transformation of the ECL images have been previously observed on the surface of the conventional disk electrode on which the microcrystals of the perylene dimer cation radical perchlorate (Pe(2)ClO(4)) were deposited. In the present work, the nanoelectrode ensembles were used for the analyses of the deposition process of Pe(2)ClO(4) and the ECL reaction. For the deposition process of Pe(2)ClO(4) with the nanoelectrode ensemble, it is confirmed that the oxidation of Pe occurs on the surfaces of the deposited Pe(2)ClO(4) and causes nucleation growth of the needle-like crystals of Pe(2)ClO(4). However, the ECL emission could not be observed using the nanoelectrode ensemble. This means that the formation of Pe(.-) in the diffusion layer is an essential factor for the ECL emission using the conventional disk electrode. In addition, the changes in the contrast of the needle-like Pe(2)ClO(4) crystals at the reduction potential indicated that the reduction of Pe(2)ClO(4) occurred. In this manner, it was found that the nanoelectrode ensembles are effective for the elucidation of the electrode reaction mechanism involving the deposition of the conducting microcrystals.