Abstract Mono-and dinuclear copper (II) complexes [Cu (L 1 OH)](CF 3 SO 3) 2 (1) and [Cu 2 (L 2 O)](CF 3 SO 3) 3 (2) have been synthesized and characterized by X-ray crystallography. Complexes 1 and 2 were then tested as catalysts for the hydrolysis of bis (p-nitrophenyl) phosphate (BNPP). At pH 6, the dinuclear complex 2 was found to be 20-fold more active than complex 1 and the reaction up to 600-fold faster than the un-promoted reaction. On ...