The preparation of optically active camphorsulphonylbenzimidazole (1), a mixture of regioisomeric 5-nitro- (2A) and 6-nitro-(2B) camphersulphonylbenzimidazoles, 5-nitro-(3A) and 6-nitro-(3B) 2-methyl camphorsulphonylbenzimidazoles is described. In this study the structure of the purified camphorsulphonylbenzimidazoles 1, 2B, 3A and 3B was confirmed by their mass and H-1 NMR spectral analysis. The specific rotation of each pure compound is also reported.