<p>The chemistry of vanadyl porphyrins has been explored using vanadyl octaethylporphyrin as a substance in petroleum porphyrins, crude oils and bitumen. The structural, electronic, thermodynamic, spectroscopic properties are described. The geometry’s optimization of this molecule was done by Density Functional Theory (DFT) using the hybrid Beck three-parameter hybrid functional combined with Lee-Yang-Parr correlation functional (B3LYP) and 6-31G(d) standard basis set. All calculations have been made in the gas phase and in different solvents: benzene, benzonitrile, tetrachloromethane and chloroform. The calculated infrared spectrum was compared with experimental spectroscopic data, and the vibrational assignment was provided. An electron density analysis in terms of natural bond orbitals was conducted to determine the nature of the bonds between the vanadium and nitrogen atoms. The spatial representation of the associated molecular orbitals helped to explain the formation of the V-N bonds and to interpret the chemical reactivity of the compound studied. The electrostatic potential was calculated in order to investigate the reaction properties of the molecule.<strong></strong></p>