We describe the preparation of the 1,3-dioxolo[4,5-b]phenazines 4 a -p formed by ferric chloride oxidation of the corresponding 2,2′-diaminodiphenylamines. They are obtained by condensing the o-nitrohalogenbenzenes 1 a -g with o-nitroanilines 2 a-i and reduction of the resulting 2,2′-dinitrodiphenylamines 3 a -p with H2/Pd.