The electrochemistry and electrochemiluminescence of two clusters [(tmeda)(6)Zn14-xMnxSe13Cl2] (tmeda=tetramethylethylenediamine, x=0 and 6) and their correlation to the spectroscopy and structures were investigated. It was discovered that these chalcogenide clusters underwent irreversible redox reactions and therefore emitted very weak ECL in the route of radical annihilation. ECL enhancement was explored by adding tetra-n-butylammonium persulfate. The [(tmeda)(6)Zn14Se13Cl2]/ persulfate co-reactant system revealed an ECL emission at 540 nm. Very interestingly, the Mn-containing cluster [(tmeda)(6)Zn8Mn6Se13C12] produced enhanced ECL with two peak wavelengths at 540 and 717 nm in the presence of persulfate. Spooling ECL spectroscopy along with the above electrochemical and spectroscopic data provided insight into ECL mechanisms and their correlation to the electronic structures of these clusters. (C) 2016 Elsevier Ltd. All rights reserved.