A process for preparing a 2-amino-benzindole of the Formula I: ##STR17## 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, comprising reducing a nitro compound of the Formula B: ##STR18## under acidic conditions to form the 2-amino-benzindole. 2.