Besides, the isomerization reaction between the two molecules, i.e., CH3NC ⇌ CH3CN, is an important prototype in the development of the unimolecular reaction theory. This isomerization reaction is favored in experiments due to its capacity to reduce the influence of side reactions and to be operated effectively at relatively low temperatures. Schneider and Rabinovitch measured its thermal rate coefficient under high-pressure conditions, and the Arrhenius factor and the activation energy were determined to be A = 10 13.6 s -1 , Ea = 1.665 eV respectively from the two fall-off curves at 472.55 K and 503.55 K. These findings were substantiated by subsequent studies that extend the rate coefficient across a broad range of temperatures and pressures. Fletcher et al. were the first to expand the study. Then follow-up studies broadened the temperature from 393.15 to 593.15 K and the pressure from 2 to 100 Torr, which led to the refinement of the Arrhenius parameters. Under such conditions, Ea was derived to be 1.656 ± 0.009 eV, while log10A became 13.35 ± 0.11. Wang et al. investigated this reaction using advanced HeI photoelectron spectroscopy, and determined Ea = 1.668 ± 0.016 eV. Besides, Reddy and Berry used a novel intracavity cw dye laser excitation technique to photoactivate CH3NC with high state selectivity, measured the stateselected isomerization rate coefficient (at Ea ≈ 1.704 eV). Since the 1970s, this isomerization reaction has been carried out by various computational methods, such as non-empirical self-consistent field SCF/DZ+P, many-body perturbation method SDQ-MBPT(4)/DZ+P, a variety of density functional theory methods in junction with several basis sets, and high-level coupled-cluster calculations integrated with the Two Dimensional Master Equation (TDME). These studies precisely calculated the structure of reactant, product, and transition state, as well as the minimum energy path (MEP), activation energy, reaction enthalpy and rate coefficient, which provide valuable insights into the title reaction.