Abstract: Improved process for the manufacture of 2,2'-imino-bis-benzothiazole compounds in which a 2-amino-benzothiazole compound is heated at a temperature of above 130.degree. C. in the presence of an acidic compound, optionally in a high boiling solvent, or in a high boiling solvent and without an acidic compound, in the latter case especially at a temperature of 200.degree. C. The high boiling solvent may preferably be an acidic solvent. The acidic compound may be used in catalytic amounts up to stoichiometric amounts. Acidic compounds are, for example, hydrochloric acid, sulfuric acid, phosphoric acid or a phenol. The 2,2'-imino-bis-benzothiazoles manufactured according to this process are obtained in pure form and high yield. They can directly be used without further purification for further processing in known secondary reactions. In the new process no difficulty accessible starting products are used, and formation of the toxic methylmercaptan according to known methods is avoided.