Within this study, four thermal ring-opening reactions, Reactions (1-4), were selected in order to investigate the phenomenon of torquoselectivity as well as predicting non-competitive or competitive reactions in QTAIM and stress tensor frameworks rather than using conventional methods. The theoretical analysis for these reactions exhibits differently for non-competitive and competitive reactions as well as for the conrotatory preferences either TSOC or TSIC directions by presenting degeneracy or non-degeneracy in their results. The concordant results of stress tensor and QTAIM scalar and vectors with experimental results provide a better understanding of all reactions mechanism. Examination the (rb), ε, H(rb), ℙσ, 3, BPL, and H indicate that Reaction 1 is a competitive and Reactions (2-4) are non-competitive reactions with TSOC, TSOC, and TSIC preference directions respectively.