Using a regioselectivity descriptor known as Fukui indices, this theoretical study examines the reactivity of cycloaddition processes of benzamide (PhCONH2) and chlorocarbonylsulfenyl chloride (ClCOSCl) at the level of base 6-311 G (d. p) by use of the DFT approach. Therefore, the attack of the sulfur atom on nitrogen and carbon on oxygen is kinetically more preferred than the assault of the sulfur atom on oxygen and carbon on nitrogen, as we have observed from our study. The electrophilic Δω difference between chlorocarbonylsulfenyl chloride and benzamide is 1.3726 eV. This indicates that the reaction under investigation has a polar nature (Δω > 1). on oxygen and carbon on nitrogen, as we have observed from our study. We have also studied the stereoselectivity and feasibility of these reactions from a thermodynamic and orbital point of view. The transition states of this reaction have been determined.