Electrochemical investigations and chemical reduction of the diiron hexacarbonyl complex bearing a 1,8-naphthalene moiety bridging linkage into which a ferrocenyl group was deliberately incorporated were performed. The complex exhibited two reduction and two oxidation processes in dichloromethane. Our results revealed that the first reduction could be assigned to an ECE (Electrochemical, Chemical and Electrochemical) mechanism with the second potential inversed. When the monoanion generated in the first reduction underwent, in part, the ECE mechanism, the rest of the monoanion continued to accept the second electron without involving a coupled chemical reaction, so called EE (Electrochemical and Electrochemical) mechanism. The two mechanisms co-existed in the electron transfer and compete with each other. By both increasing scanning rate and lowering temperature, the coupled reaction in the ECE mechanism could be effectively suppressed whereas the second reduction is highly irreversible. The coupled chemical reaction following the EE process might lead to the same dianion as that produced in the ECE processes. Although chemical reduction and re-oxidation were unsuccessful of confirming the transformation between the two dianions, DFT calculations did support this proposed chemical reaction. (C) 2015 Elsevier Ltd. All rights reserved.