A direct one-step preparation of triarylverdazylium salts from the corresponding triarylformazans

6-(4-Substituted-phenyl)-2,4-diphenylverdazylium salts 2 (8 examples, 55-93 %) were prepared by the reaction of 3-(4-substituted-phenyl)-1,5-diphenylformazans 1 with formaldehyde and different organic and inorganic acids in a two-phase chloroform/water medium by brief and gentle heating. Self-phase-transfer catalysis is apparently involved. Subsequent reductions of the salts 2 with excess ascorbic acid in the two-phase system give the corresponding verdazyl radicals, while in methanol the reduction proceeds to form leuco-verdazyls.