Detergent compositions comprise brightening agents of the formula <FORM:0935515/III/1> wherein R1 is a monocyclic aromatic hydrocarbon residue containing 6 to 8 carbon atoms, R2 is a C1-4 alkyl group which may be substituted by 1 or 2 hydroxyl groups, and R3 is a C1-2 alkyl group.  Detergents mentioned are soaps; salts of sulphonate detergents, such as sulphonated benzimidazoles containing higher alkyl groups on carbon atom 2; salts of monocarboxylic acid esters of 4 sulphophthalic acid with higher fatty alcohols; salts of fatty alcohol sulphonates, alkyl aryl sulphonic acids or condensation products of higher fatty acids with aliphatic hydroxy- or aminosulphonic acids; non-ionic detergents such as polyglycol ethers derived from ethylene oxide and higher fatty alcohols, alkyl phenols or fatty amines.  The detergents may also contain conventional additives such as alkali metal carbonates, phosphates, pyrophosphates, polyphosphates, metaphosphates, silicates, perborates, or percarbonates provided that the brightening agent is compatible with such additives.  The mixtures may be prepared by mixing or grinding the ingredients together, and it is of advantage to use one component as a melt or in the dissolved state.  The brightening agent may also be used to treat oils and fats.ALSO:Brightening agents of the formula <FORM:0935515/IV(a)/1> wherein R1 is a monocyclic aromatic hydrocarbon residue with 6 to 8 carbon atoms, R2 is an alkyl radical containing 1 to 4 carbon atoms which may be substituted with 1 or 2 hydroxyl groups, and R3 is a C1-2 alkyl group, may be added to spinning compositions of linear synthetic polyamides.ALSO:The invention comprises compounds of the formula <FORM:0935515/IV(a)/1> and their water-soluble salts wherein R1 is a monocyclic aromatic hydrocarbon residue with 6 to 8 carbon atoms, R2 is an alkyl radical containing 1 to 4 carbon atoms which may be substituted with 1 or 2 hydroxyl groups, R3 is a C1-2 alkyl group; and their preparation by reacting cyanuric chloride with 441 diaminostilbene-2,21-disulphonic acid, an amine HNR1R2 and an alkanol HOR3 in the molecular proportions 2:1:2:2 in any order of succession. Preferably the product from the reaction of the alkanol with cyanuric chloride is reacted first with 4,41-diaminostilbene-2,21-disulphonic acid and then with the amine HNR1R2, in a solution at a gradually rising pH or in the presence of an acid acceptor, e.g. ethanolamine or excess HNR1R2.  Examples are given of the preparation of various compounds of the above formula in which R3 is ethyl or methyl and R2 is methyl or ethylol. The compounds may be used as brightening agents in the treatment of textiles and other fibrous materials, polymeric material, fats, edible carbohydrates and cosmetics (see Groups I, IV(a), IV(c) and VI) and in detergent compositions (see Group III).ALSO:Brightening agents of the formula <FORM:0935515/IV(a)/1> wherein R1 is a monocyclic aromatic hydrocarbon residue with 6 to 8 carbon atoms, R2 is a C1-4 alkyl group which may be substituted with 1 or 2 hydroxyl groups, and R3 is a C1-2 alkyl group, may be used as additives to paper pulp; in admixture with dyestuffs or as additives to dye liquors and for aftertreating dyeings, prints or discharge effects; in admixture with chemical bleaches or as additives to bleaching baths; in admixture with starch or synthetic dressing agents; as additives to washing liquors with detergents; for the treatment of textile materials such as cotton, hemp, flax, linen, jute, ramic, regenerated cellulose, e.g. rayon and viscose, cellulose esters and also synthetic materials such as polyesters and polyamides; for the treatment of other fibrous materials which may be feathers, hairs, pelts, skins, leathers, straw, wood, wood pulp, paper, cardboard, hardboard and products made therefrom.  Examples illustrate the treatment of bleached cotton fabric and bleached polyamide fabric.ALSO:Flour is treated with a brightening agent,ALSO:Brightening agents which are used for treating sugar or in the preparation of cosmetics such as toothpastes, hair dressings and tonics, and sunburn preparations are bis-triazinyl-aminostilbene-disulphonic acids of the formula <FORM:0935515/VI/1> or water-soluble, e.g. sodium, salts thereof, wherein R1 is a monocyclic aromatic hydrocarbon residue with 6 to 8 carbon atoms, R2 is a C1-4 alkyl group which may be substituted by 1 or 2 hydroxyl groups, and R3 is a C1-2 alkyl group.