The in situ copper (II) complexes of six pyrazole and pyridine based ligands: 1-[5-methyl-1-pyridin-2-yl-1H-pyrazol-3-yl] methanol L-1, 2-(3,5-dimethyl-pyrazol-1-yl)-pyridine L-2, (5-methyl-3-pyridin-2-yl-1H-pyrazol-1-yl) ethyl acetate L-3, 1',5,5'-trimethyl-1'H-1,3'-bipyrazol-3-ethyl carboxylat L-4, (1',5,5'-trimethyl-1'H-1,3'-bipyrazol-3-yl) methanol L-5, and 5,5'-diphenyl-3,3'-bipyrazole L-6, are reported and studied for their catecholase activities at ambient conditions, the reaction rate depends on four parameters: The nature of the carbonic chain bounded to the pyrazole ring, the nature of counter anion, the concentration of ligand and the nature of solvent. The highest rate activity is given by complex resulting from one equivalent of ligand L-4 and two equivalents of Cu(CH3COO)(2) in methanol, which equal to 4.440 mu mol min(-1). (C) 2013 Elsevier B.V. All rights reserved.