Abstract: A mixture of yellow azo- and azoxystilbene dyes having the shade of a C.I. Direct Yellow 11 dye is obtainable from the self-condensation of 4,4′-dinitro-2,2′-stilbenedisulfonic acid in the presence of an alkali metal hydroxide and an excess of formaldehyde beyond that needed for the conversion of 4,4′dinitro-2,2′-stilbenedisulfonic acid to Direct Yellow 6. Concentrated aqueous solutions of the dyes are obtainable by converting the sparingly soluble alkali metal salt of the dye into a water-soluble alkanolammonium salt by a double cation exchange via a lipophilic ammonium salt, in which process the double ion exchange is carried out in a two-phase system of methyl isobutyl ketone/water and using, for the first ion exchange a trialkylamine containing a total of 12 to 40 carbon atoms and, for the second ion exchange, a mono-, di- or trialkanolamine containing 2 to 4 carbon atoms in each alkyl moiety. The dyes are especially useful for dyeing paper.