In Section 3, we obtained FB-ENM paths for several reactions where IDPP provides highenergy paths. In these reactions, FB-ENM paths successfully yielded the plausible path, while IDPP paths exhibited undesired molecular distortions and bond breakings. Notably, it was revealed that the rotational isomerization of 9,9'-bianthracene, used in ref 18 to demonstrate the improved NEB method for IDPP, rather highlights IDPP's vulnerability.