Our combinatorial robot system is able to automatically make a combinatorial library, which comprises (n x n) samples synthesized in the wells on a platinum reaction plate. An electrode array was developed for the high-throughput evaluation of the library. It has multiple counter electrodes, and its attachment to the library forms (n x n) electrochemical cells, which are operatable individually. In case of n = 4, the evaluation was completed within 3 h, indicating that the combination of our robot system and our electrode array is very efficient for the exploration of new electrode materials. (C) 2003 Published by Elsevier B.V.