Azo dyes are produced by coupling diazo compounds with bis-(2 : 3-oxynaphthoyl)-4 : 41 diamino-3 : 31-dialkyloxydiaryls; the dyestuffs may be produced upon a substratum or upon the fibre, various shades of brown being thereby obtained. As diazo compounds may be used those of aniline and its substitution products, such as toluidines, anisidines, chlor- and nitro-anilines, chlor- and nitro-toluidine, chlor- and nitro-anisidines, naphthylamines, aminoanthraquinones, aminoazo-compounds, and diamines; nitrosamines may also be used. Prints may be produced by printing with diazo solutions upon goods padded with the 2 : 3-oxynaphthoic acid derivative. In an example an orange-brown shade is produced on cotton yarn impregnated with bis-(2 : 3-oxynaphthoyl)-dianisidine by developing, without drying, in a solution of diazotized 2 : 5-dichloraniline. A table is given showing the shades obtainable from bis-(2 : 3-oxynaphthoyl)-dianisidine or bis-(2 : 3-oxynaphthoyl)-diphenetidine on the one hand and the diazo or tetrazo compounds of the following bases:-o-toluidine, m-chloraniline, 2 : 5- or 3 : 5-dichloranaline, 4- or 5-chlor-2-toluidine, 4-chlor-3-toluidine, 4-chlor-2-anisidine, 4- or 5-nitro-2-toluidine, 3-nitro-4-toluidine, 4- or 5-nitro-2-anisidine, 5-nitro-3-anisidine, 4- or 5-chlor-2-nitraniline, 2- or 3-chlor-4-nitraniline, 3 : 5-dinitraniline, 4-nitro-anthranilic acid methyl ester, 5-nitro-3-aminobenzoic acid ethyl ester, a -aminoanthraquinone, m-aminoazotoluene, benzidine, dianisidine. Bis-(2 : 3-oxynaphthoyl)-4 : 41-diamino-3 : 31-dialkyloxy-diaryls are obtained by the action of 2 : 3-oxynaphthoic acid on 4 : 41 diamino-3 : 31-dialkyloxydiaryls; the properties of the compounds from dianisidine and diphenetidine are given.ALSO:Fast brown shades are produced upon the fibre by impregnating with a bis-(2 : 3-oxynaphthoyl)-4 : 41-diamino-diaryl and developing with a diazo compound; the latter may be applied by printing. As diazo compounds may be used those of aniline and its substitution products, such as toludines, anisidines, chlor- and nitro-anilines, chlor- and nitro-toluidines, chlor- and nitroanisidines, naphthylamines, aminoanthraquinones, aminoazo compounds, and diamines; nitrosamines may also be used. In an example an orange-brown shade is produced on cotton yarn by impregnating with bis-(2 : 3-oxynaphthoyl)-dianisidine and developing, without drying, in a solution of diazotized 2 : 5-dichloraniline. A table is given showing the shades obtainable from bis-(2 : 3-oxynaphthoyl)-dianisidine or diphenetidine on the one hand and the diazo or tetrazo compounds of the following bases:-o-toluidine, m-chloraniline, 2 : 5-or 3 : 5-dichloraniline, 4- or 5-chlor-2-toluidine, 4-chlor-3-toluidine, 4-chlor-2-anisidine, 4- or 5-nitro-2-toluidine, 3-nitro-4-toluidine, 4- or 5-nitro-2-anisidine, 5-nitro-3-anisidine, 4- or 5-chlor-2-nitraniline, 2- or 3-chlor-4-nitraniline, 3 : 5-dinitraniline, 4-nitro-anthranilic acid methyl ester, 5-nitro-3-aminobenzoic acid ethyl ester, a -aminoanthraquinone, m-aminoazotoluene, benzidine, dianisidine.