The cycloaddition of tetracyanoethylene oxide (TCNEO) with benzene and benzene derivatives, and the subsequent evolution of the corresponding cycloadducts is theoretically investigated using DFT and highly correlated ab initio calculations. Both the relative reactivity of the different aromatic compounds, as well as the regioselectivity of the cycloaddition is explained in light of the theoretical study. Insights in the formation of arylmalononitriles, which gives potential synthetic applications to this process, are also offered.