A Ni/NiO catalyst is reported for converting a phenolic compound, such as guaiacol, and cashew nut shell liquid (CNSL) into different hydrocarbons. High guaiacol conversion (80%) and higher cyclohexane selectivity (23%) over the Ni/NiO catalyst are reported in comparison to the other reported Ni-based catalysts at a temperature of 300 degrees C and 50 bar H-2 pressure. The CNSL hydrodeoxygenation (HDO) activity increased with the temperature and reached a maximum conversion (100%) at 300 degrees C. The high total acidic sites of Ni/NiO favored the high conversion (100%) with 15% cyclohexane selectivity, 30% phenol selectivity, and maximum selectivity for tetradecane (45%) in CNSL HDO. This is the first such report to the best of our knowledge. The Ni/NiO catalyst was characterized by X-ray diffraction (XRD), transmission electron microscopy, X-ray photoelectron spectroscopy, temperature-programmed desorption of ammonia, N-2 sorption, X-ray absorption near edge structure, and X-ray absorption fine structure (XAFS). The products were analyzed by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance, gas chromatography, and gas chromatography-mass spectrometry. XRD analysis showed that NiO crystallinity decreased while Ni crystallinity increased after reduction. XAFS analysis confirmed that the metallic Ni nature increased after reduction, as indicated by a decrease in the Ni-Ni1(Ni) bond distance from 2.596 angstrom for unreduced Ni/NiO to 2.519 angstrom (closer to that for the metallic Ni face-centered cubic phase) for the reduced sample, which would result in improved hydrogenation activity of the reduced catalyst. The spent Ni/NiO catalyst showed good stability without any phase change during the reaction and retained its original structure.