A process of preparing a 2-amino-benzindole of the Formula I: ##STR21## wherein X is a hydrogen atom, a halogen atom, an alkyl group or a thioether group and Y is an amine group, a thioether group or an alkyl group, which process comprises: reducing a nitro compound of the Formula B ##STR22## and treating the reduction product with an acid to form the 2-amino-benzindole. 8.