A dihydroxybenzenes(DHB)-driven Fenton reaction was found to be more efficient than a simple Fenton reaction based on (center dot)OH radical and activated species production. The reason for this enhanced reactivity by [Fe DHB] complexes is not well understood, but results suggest that it may be explained by the formation of oxidation species different from those formed during the classic Fenton reactions. In previous work, greater concentrations, and more sustained production of (center dot)OH over time were observed in DHB driven Fenton reactions versus neat Fenton and Fenton-like reactions. In this work, chemiluminescence (CL) was monitored, and compared to (center dot)OH production kinetics. The CL of the DHB-driven Fenton reaction was shorter than that for sustained production of (center dot)OH. CL appears to have been caused by excited Fe(IV) species stabilized by the DHB ligands initially formed in the reaction. Formation of this species would have to have occurred by the reaction between (center dot)OH and Fe(III) in a DHB complex. (C) 2011 Elsevier B.V. All rights reserved.