A mononuclear square planar Ni(II) complex [NiIIL] (1) with sterically encumbered phenol based tetra dentate N2O2 ligand has been synthesized. Several spectroscopic tools have been employed to characterize this complex. The crystal structure of this Ni(II) complex obtained from single crystal X-ray diffraction study reveals that the central metal ion adopts a square planar environment and crystalized in monoclinic space group C 2/c with a = 24.1784 (10), b = 9.3537 (4) and c = 8.3326 (4) with β = 97.0690 (11). The Hirshfeld surface analysis shows halogen-halogen interaction. The Ni(II) complex has been found to be an effective catalyst for the aerial oxidation of 3,5-DTBC to 3,5- DTBQ in methanol. For kinetic study, Michaelis-Menten model has been approached to determine the Kcat, KM and Vmax. The kinetic studies confirm that the turnover number (TON) of complex 1 is 1.762 × 103 h−1. © 2019 Elsevier B.V.