The reactivity of E-and Z-phenylhydrazones of 3-benzoyl-5-phenyl-1, 2, 4-oxadiazole in the presence of CuCl2 and Cu (ClO4) 2· 6H2O has been studied in four imidazolium ionic liquids [bmim][X](X= BF4−, PF6−, SbF6− and CF3SO3−). The reaction may follow different mechanistic patterns, depending on the nature of the ionic liquid anion, accounting for both qualitative and kinetic data. In the presence of CuCl2, two processes take place at the ...