N, N'-Diarylformamidines have been prepared by the interaction of substituted formanilides with ariilines in the presence of phosphorus pentachloride, in chloroform medium. The homodisubstituted amidines were obtained in yields up to 70%. Heterosubstituted amidines could be prepared by two different routes but usually were contaminated with the corresponding homodisubstituted compounds. Ethoxy-, carbethoxy-, amino-and nitro ...