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The oxygen molecule plays an important role in the biosphere. It participates in the respiratory aerobic processes of life, protects living organisms from harsh solar radiation and is responsible for the processes of combustion and slow oxidation. The details of many chemical and physical phenomena involving the O2 molecule are associated with the presence of low-energy singlet excited states, a nonzero magnetic moment in the ground triplet state and the metastable quintet state of the oxygen molecule. Electronic transitions between these states in the electric dipole approximation are strictly forbidden by spin, by orbital angular momentum projection, and by parity. Delocalization of the spin density, change of the π electronic structure due to O2(5Пg) collision with aromatic molecule has not been studied so far. Such studies may help to understand the mechanism of energy transfer upon interaction between aromatic molecules and metastable O2*. Therefore, we study here the properties of the O2(5Пg) + C6H6 complex because benzene is an aromatic molecule with a high polarizability. In our paper we present study of the O2(5Пg) interaction with benzene molecule using the powerful UB3LYP/6-311++G(d,p) approach of DFT method. We have started from the very big collision distance of 3 Å and performed geometry optimization until we get a tightly bound addition product. This leads us to the formation of two new C-O˙ bonds in the associate of O2(5Пg) molecule and benzene without barrier. By using such a simple approach, we were able to purify the configuration state function, which is a complicated multi-electron problem that occurs at the first-principles computational level. Collected results are very important in estimating the effect of oxygen on the aromaticity and reactivity of benzene and other organic unsaturated substances.