A novel electrochemiluminescent reagent, 2,6-Diethyl-1,3,5,7-tetramethyl-8- [(2-fluorophenyl)-6-methoxy-1,5-naphthyridine-3-carboxy]-4,4′- difluoroboradiazaindacene, BODIPY-COOH, capable of direct conjugation to a wide range of biomolecules has been developed. BODIPY-COOH shows a high fluorescence quantum yield, φ = 0.67 ± 0.03, which significantly exceeds the range of 0.33 to 0.41 previously reported for structurally similar dyes. In the presence of persulfate, the dye generates significant electrochemiluminescence, ECL. Significantly, at high concentrations, quenching of the ECL is observed due to dimerisation. © 2012 Elsevier B.V. All rights reserved.