To test our EDC analysis tool, we considered six representative unimolecular and bimolecular reactions: (A) the identity S N 2 reaction; (B) the Claisen rearrangement of allyl vinyl ether; (C) the Diels-Alder cycloaddition between cyclopentadiene and acrylonitrile; (D) the [3+2] cycloaddition of the azomethine ylide pseudoradical with ethylene; (E) the S N 2 reaction between pericosine A and phenylethyl mercaptane; and (F) the splitting of N 2 O bound to copper triflate. When multiple bond forming and breaking are involved, some of the above reactions are asynchronous (such as the example Claisen rearrangement, Diels-Alder, and pericosine reactions), whereas others are concerted (such as the identity S N 2 and [3+2] cycloaddition). While most of the reactions are spin-conserving, the last reaction involves a crossing from a singlet surface of the N 2 O-Cu-Triflate complex to the triplet one. Besides the EDC plots shown in the following main text, the EDC movies of the studied reactions and the reaction energy profiles can be found in the supporting information (SI). Bimolecular nucleophilic substitution S N 2 reactions are widely studied both experimentally and theoretically. Here, we shall use the identity S N 2 reaction between methyl chloride and chloride anion to test our new EDC method. The reactant structure (Fig. ) was constructed from two fragments, namely chloride anion (Cl - A ) and methyl chloride (CH 3 Cl B ), which were separated by a Cl A -C distance of 3.22 Å. The nucleophilic attack of the chloride anion led to the transition state in Fig. . At the transition state, the carbon atom of the methyl chloride is equidistant from two chlorine atoms with both C-Cl A and C-Cl B distances being 2.34 Å. From the TS structure, the product was generated with the C-Cl A bond distance of 1.82 Å, and chloride anion (Cl - B ) as the leaving group. Fig. showed the electron density change from the reactant to the transition state. As expected, it showed a decrease in the electron density from the C-Cl B σ bond (shown in magenta) of methyl chloride and the emergence of a new bond (shown in blue) between Cl A and the carbon atom of the methyl chloride. In this stage, the three C-H bonds of methyl chloride also gained a minor increase in their electron densities. A complete formation of the Cl A -C bond (with a large blue cloud) and the further weakening of the C-Cl B bond could be seen during the subsequent transition from TS to the product in Fig. . Movies showing the EDC for entire pathway can be found in the supporting information for all reactions studied in our work, with sn2_iso02.mp4 for the identity S N 2 reaction.