The present work envisages an eco-friendly route for N-oxidation of heterocycles and selective mono N-oxidation of substituted pyrazines in good yields using 30% dilute H2O2 as an oxidant together with redox molecular sieves (TS-1, Ti-ZSM-5 (30), Ti-MCM-41) as catalysts in aqueous and non-aqueous medium as solvent. The TS-1 catalyst is shown good activity and selectivity in N-oxidation of substituted pyridines and pyrazines except -cyano substituted pyridines and pyrazines. The activity has been enhanced with TS-1 catalyst in aqueous medium in comparison with non-aqueous medium as solvent when electron-withdrawing groups are present. The solid catalysts displayed consistent activity for several cycles. (C) 2002 Elsevier Science B.V. All rights reserved.