In the present study, hydroxyl functionalized nickel(II) Schiff-base; [Ni((OH)(2)-salophen)] [(OH)(2)-salophen] = (N,N'-bis(4-hydroxysalicylidene)phenylene-1,2-diamine); has been covalently anchored on modified multi-wall carbon nanotubes (MWNTs); [Ni((OH)(2)-salophen)]@MWNTs]. The new modified MWNTs have been characterized by transmission electron microscopy (TEM), thermal analysis, UV-Vis, Diffuse reflectance (DRS), FT-IR spectroscopy and elemental analysis. The results suggest that the symmetrical Schiff-base is a bivalent anion with tetradentate N2O2 donors derived from the phenolic oxygen and azomethine nitrogen. Multi-wall carbon nanotubes which covalently anchored nickel(II) complex catalyze the oxidation of cyclohexene with molecular oxygen. (C) 2015 Elsevier B.V. All rights reserved.