Abstract A procedure has been developed for the synthesis of bis (2-arylcarbonylamino-1 H- benzimidazol-5-yl) sulfones by reaction of the corresponding substituted benzoyl chloride with sodium cyanamide and subsequent treatment of the N-cyanobenzamide thus formed with 3, 3′, 4, 4′-tetraaminodiphenyl sulfone in acid medium. The products were tested for fungicidal activity.