While quantum dots (QDs) have attracted much interest in electrogenerated chemiluminescence (ECL) as a light emitter due to their high quantum yield and bandgap tunability, the fundamental ECL characteristics of QDs in various conditions still remain elusive. In this study, we investigate the ECL generation from CdTe QDs dispersed in organic solvents in the presence of a coreactant. ECL generation via the annihilation between the radical cation of CdTe QDs and their radical anion is not efficient because of the short-lived, unstable radical cation of CdTe QDs. The coreactant, tetra-n-butylammonium peroxydisulfate, can facilitate the ECL generation from CdTe QDs via more efficient generation of the radical cation formed by direct oxidation of the radical anion of CdTe QDs. A poor ECL emitter, Ir(III) complex ((pq)(2)Ir(dbm)), is examined as a novel coreactant for CdTe QDs, and it turns out that this new ECL system is a very efficient ECL generator. This great improvement is attributed to the collaborative enhancement of ECL from both CdTe and (pq)(2)Ir(dbm). (C) 2011 Elsevier B.V. All rights reserved.