Nanodimensional microreactor containing (3,10-dialkyl-dibenzo-1,3,5,8,10,12-hexaazacyclotetradecane)copper(II) complexes have been prepared by the one-pot template synthesis of formaldehyde and 1,2-phenylenediamine (1,2-phen) with alkyl and benzyl amine within the pores of zeolite-Y. The copper(II) complexes were entrapped in the supercage of Y-zeolite by a two-step process in the liquid phase: (i) inclusion of a copper(II) precursor complex, [Cu(1,2-phen) 2 ] 2+ -NaY, and (ii) template condensation of the copper(II) precursor complex with the formaldehyde and amine. The spectra of the neat and encapsulated complexes show that the four secondary nitrogen atoms are coordinated to the copper(II) ion. Encapsulated copper(II) complex is catalytically very efficient as compared to other neat complexes for the partial oxidation of benzyl alcohol with hydrogen peroxide as oxidant and is stable to be recycled without much deterioration.