The invention comprises dyes which contain at least one group of formula <FORM:0927773/IV(a)/1> where R is H or a substituted or unsubstituted alkyl or cycloalkyl radical, Z is a 1,3,5-triazine or pyrimidine ring which is attached to N through a C atom of the ring and which carries at least one group of formula <FORM:0927773/IV(a)/2> each of which is attached to a C atom of the ring, where R1 and R11 are H or substituted or unsubstituted hydrocarbon radicals and may be the same or different. The <FORM:0927773/IV(a)/3> groups are attached to carbon atoms in the dye molecule. The carbon atoms may be part of the aryl residues of the dye or of alkyl chains which are directly attached to aryl residues in the dye or are attached through bridging atoms or groups. The dyes may be made by treating a dye which has at least one group of formula <FORM:0927773/IV(a)/4> where Z1 is a 1,3,5-triazine or pyrimidine ring attached to N via a C atom of the ring and has at least one halogen atom, with a compound of formula <FORM:0927773/IV(a)/5> where W is a hydrogen or a metal atom, e.g. sodium or potassium. The azo dyes may also be made by conventional diazotization and coupling processes. Alternatively, dyes with at least one NHR group may be reacted with an appropriate halo-triazine or pyrimidine. Halogen atoms in the triazine or pyrimidine ring of the final products may be converted to other substituents. Nitro, anthraquinone, phthalocyanine and azo dyes are mentioned, the latter, especially mono- or -polyazo, being preferred. Water-solubilizing groups, e.g. alkylsulphone, sulphonyl, carboxylic acid and sulphonic acid groups, the last-named being preferred, may be present. Co-ordinately bound metals, e.g. copper, chromium and cobalt, may be present. Illustrative of specified values for R1 and R11 are methyl, butyl, b -hydroxyethyl, b -ethoxyethyl, benzyl, cyclohexyl, tolyl and naphthyl. Examples of other specified groups attached to a carbon atom of the triazine or pyrimidine ring which may be present, together with the group indicated above, are bromine, carboxymethylmercapto, ethyl, phenyl, hydroxy, propoxy, sulphophenoxy, amino, b -hydroxy-ethylamino, dimethylamino, disulphoanilino, sulphonaphthylamino, diethyldithiocarbamyl, nitro, cyano, thiocyano and sulphonic acid groups. R is preferably a lower alkyl radical which may contain substituents such as hydroxy or methoxy groups. R is also specified as a cyclohexyl group. Specified as linking atoms or groups are <FORM:0927773/IV(a)/6> , -SO2NH, -CONH- and -SO2N-alkyl. Indicated as starting materials are compounds of formula <FORM:0927773/IV(a)/7> where D1 is an at most dicylic aryl radical, e.g. stilbene, diphenyl, diphylamine and benzthiazolylphenyl, free from azo and NHR groups, the NHR group is preferably in the 6, 7 or 8 positions and a sulphonic acid group may be in positions 5 or 6 and the NHR group may also be attached to the nucleus via a benzoylamino or anilino group; compounds of the formula immediately above where D1 is an azobenzene, azonaphthalene or phenylazonaphthalene residue; monoazo compounds of formula <FORM:0927773/IV(a)/8> where D1 is as above, preferably a disulphonaphthyl or stilbene radical and the benzene nucleus may be substituted; mono- or dis-azo compounds of formula RN(H)D1-N=N-K where D1 is as above, preferably on at most dicyclic arylene radical of the benzene or naphthalene series and K is the residue of a naphthol sulphonic acid or an enolised or enolizable ketomethylene compound; mono- and dis-azo compounds of formula D1-N=N-K2-NHR where D1 is as above and K2 is an enolizable ketomethylene radical; metal complexes of the above metallizable dyes, anthraquinones of formula <FORM:0927773/IV(a)/9> which may have a sulphonic acid group in positions 5, 6, 7 or 8, and where Y is a bridging group, preferably a divalent residue of the benzene series, e.g. phenylene, diphenylene and 4,41-stilbene and azobenzene radicals, and preferably Y contains one sulphonic acid group for each benzene ring present, phthalocyanine compounds of formula (SO2-W)n-Pc-(SO2NH-Y-NHR)m where Pc is preferably a phthalocyanine residue, W is OH and/or NH2, Y is a bridging group, preferably an aliphatic, cycloaliphatic or aromatic group, n and m are 1, 2 or 3 but n + m must not be greater than 4, and nitro compounds of formula NO2-A-NH-B-NHR where A and B are monocyclic aryl nuclei with the NO2 group o to the NH group. Preferred classes of dyes are water-soluble dyes, containing at least one sulphonic acid group, and one or two groups of formula <FORM:0927773/IV(a)/10> or <FORM:0927773/IV(a)/11> or <FORM:0927773/IV(a)/12> where A is an amino, or substituted amino group, preferably a sulphonated phenylamino group, or <FORM:0927773/IV(a)/13> or <FORM:0927773/IV(a)/14> or <FORM:0927773/IV(a)/15> where R1 is an alkyl, preferably methyl, group, Z1 is a pyrimidine ring, halogen is Cl or Br, n is 1 or 2 and X is H or Hlg. The dyes colour natural and artificial textile materials, e.g. those comprising cotton, viscose rayon, regenerated cellulose, wool, silk, cellulose acetate, polyamides, polyacrylonitriles, which may be modified, and aromatic polyesters. Water-soluble dyes containing such groups as sulphonic acid and carboxylic acid are preferably applied to cellulosic material in conjunction with treatment by an acid-binding agent. Dyes which do not have water-solubilizing groups are applied as aqueous dispersions. Nitrogen-containing materials are treated in a mildly alkaline, neutral or acid bath. Resin-forming compounds and acidic catalysts may also be used in the colouring processes. Examples are provided of the preparation of a great many dyes and their use in colouring processes to produce a variety of colour shades. Specifications 209,723, 298,494, 467,815, 503,609, 772,030, 774,925, 775,308, 780,591, 781,930, 784,221, 785,120, 785,222, 797,946, 802,935, 803,473, 805,565, 822,047, 822,948, 825,377, 826,405, 828,353, 829,042, 832,400, 833,396, 834,304, 836,248, 836,647, 837,035, 837,124, 837,953, 837,985, 837,990, 838,311, 838,335, 838,337, 849,772, 851,537, 852,120, 852,911, 863,754, 864,227, 869,279, 870,985, 872,249, 874,544, 876,092 and 885,059, and U.S.A. Specification 2,258,977 are referred to. The Provisional Specification also refers to Specifications 838,307, 838,340, 838,341, 838,342, 838,343, 838,344, 838,345, 838,728, 844,869, 859,198, 863,758, 864,080, 876,632, 877,178 and 877,249.