Reaction of copper(II) complex 1(X) supported by the tridentate bis(pyridylmethyl)amine ligand containing m-substituted phenyl groups at the 6-positions of the pyridine rings (L-X) with H2O2 in the presence of triethylamine (NEt3) in acetone generates a copper(II)-alkylperoxo species 2(X) [2-hydroxy-2-hydroperoxypropane (HHPP) adduct]. The alkylperoxo intermediate 2(X) undergoes an efficient aromatic ligand hydroxylation reaction, producing a phenolate complex 4(X) via another intermediate 3(X). Kinetic studies on the aromatic hydroxylation process are reported together with spectral characterization of 2(X).