[en] We have concluded that the apparent pKa values of the substrates reflect the differences in the k_H values and k_o values, the hydrolysis reactions of N-benzoyl-4,5-diphenylimidazoles are not catalyzed by the general base, the geometry of the leaving group in the hydroxide ion catalyzed reaction is very important and the substituent effect on the hydroxide ion catalyzed reaction appears very large. Recently, we have reported hydrolysis reactions of three N-acylimidazoles compounds having one phenyl substituent in the imidazole leaving group. In the hydrolysis reaction of N-furoyl- and N-thenoyl-2-phenylimidazole of these three compounds observed a change in rate determining step in acidic region, whereas, that of N-benzoyl-2-phenylimidazole found to be related with the diprotonated species in acidic region. Even though, the change in the structure of N-acylimidazoles, sometimes, give rise to an abnormal reactivity in hydrolysis reaction,2 the feature of the hydrolysis of the above three N-acyl-2-phenylimidazoles compounds was very unique in comparison with the previous obtained results from hydrolysis of N-acylimidazole derivatives