Reduction of benzotrifuroxan with triphenylphosphine did not yield the expected compound, benzotrifurazan. Five coloured compounds were isolated and their structures have been determined by crystallographic methods. These compounds are 1,3,5-trinitro-2,4,6-tris(triphenylphosphoranylideneamino)benzene (III); the hydroxy-triphenylphosphonium salt of (IV); 4-nitroso-5-triphenyl-phosphoranylideneaminobenzo[1,2-c : 3,4-c′]difurazan (V); 5-triphenylphosphoranylidenebenzo(1,2-c:4,5-c′)difurazan-4(5H)-one 3,8-dioxide (VI); and 8,8′-bis(triphenylphosphoranylidene)bi(benzo[1,2-c:4,5-c′]-difurazan-4-ylidene)(VII).