Under the optimized reaction conditions, the reaction curve of p-methylnitrobenzene 2a showed that 2a was rapidly consumed within 4 hours to form 2c (Figure ). In the early stage of the reaction, the intermediate compound 2e gradually increased and reached the highest amount within 2 hours and then decreased gradually after 2 hours. Interestingly, another intermediate compound 2f continuously stays at a low level with the emergence of 2e. The intermediate amine 2b also slowly increased to the maximum in 4 h, which is consistent with the result that the starting material 2a was completely consumed at 4 h. Then the intermediates compound 2b, 2e was gradually transformed into 2c, which was consistent with the observed selectivity. Then, to support the hydrogen borrowing mechanism and determine that the reaction intermediates are involved in the reaction, 1b, 1c, 1e, and 1f are used as the substrates for the reaction under the optimized conditions. It is found that 1b and 1e are all reaction intermediates, and once 1c is produced, it is difficult to reverse the reaction. According to the reported kinds of literature, it is speculated that the hydrogen transfer reduction of nitrobenzene to aniline occurs in two ways, and then N-methylaniline is synthesized by N-methylation of aniline. One way is that nitrobenzene is reduced to N-phenylhydroxylamine by intermediate nitrosamine with the help of hydrogen transfer, which is directly dehydrated to aniline. The other path is the reductive coupling of nitrosamine with N-phenylhydroxylamine to get azobenzene by oxidation of azobenzene, which is further reduced to aniline by 1,2-diphenylhydrazine. From the analysis of mechanical inquiry dynamics, the second path plays a major role in it. Then, as previously reported, aniline was dehydrogenated with methanol to form the intermediate N-phenylmethylimine, and then continued to be reduced to Nmethylaniline (Figure ).