The carbodiimides 2, obtained from aza-Wittig reactions of vinyl iminophosphorane 1 with aromatic isocyanates, reacted with hydrazine to give 1-amino-2-arylamino-4-arylidene-4,5-dihydro-imidazol-5-ones (4). One-pot reactions of 4 with isocyanates (or acyl chlorides), triphenyl phosphine, hexachloroethane and triethylamine produced 2-anilino (or methyl)-5-arylidene-1- aryl-4,5-dihydroimidazo[1,2-b]-1',2',4'-triazol-4-ones 6 (or 7) in good yields. The biological activities of the new heterocycles synthesized were investigated and the results showed that some of the compounds exhibited good fungi...