The invention comprises dyestuffs of formula <FORM:0757047/IV(c)/1> where Me is a nickel or copper atom bound in complex union, Y is -CH=CH or a direct bond, Py is a pyrazolone residue, R1 and R2 are benzene residues, R3 is a benzene or napthalene residue bound in para-position to the azo-linkages, R4 is a naphthalene residue, the azo linkages bound to R1 and R2 are in para-position to Y and the -O-Me-O- group is connected to R3 and R4 in positions vicinal to the azo linkage. They are made by metallizing in conventional fashion the corresponding o-alkoxy, o1-hydroxycompound, R4 containing the hydroxy group. Theoalkoxy, o1-hydroxy compound may be made by coupling a tetrazo compound of a diamine of formula H2N-R1-Y-R2-NH2 with a pyrazolone, advantageously in a weakly acid medium, and with an appropriate amine as middle component in a weakly acid to weakly alkaline medium diazotizing the amino diazo dyestuffs thus obtained and coupling with the necessary naphthalene derivative. Alternatively the diamine may be diazotized and coupled with the pyrazolone, the resulting dyestuff diazotized and coupled with the middle component and the preparation completed as above. They may also be made by diazotizing a compound of formula A-R2-Y-R2-A where one A is NH2 and the other a group convertible to NH2 and the other a group convertible to NH2, coupling with a pyrazolone, converting the remaining A to NH2, diazotizing the monazo dyestuff thus obtained and coupling with an appropriate middle component and then proceeding as in the previous preparations. Alternatively in the preparation of the previous sentence initial coupling may be effected with the middle component and the dyestuff thus obtained diazotized and coupled with the end component before the remaining A is converted to NH2 and the coupling with the pyrazolone effected. Coupling with the end component is preferably effected in an alkaline medium in the presence of pyridine or picoline. The diamines used may contain further substituents such as chlorine, methyl, ethoxy, methoxy and sulphonic acid groups, those specified being 4, 41- diaminodiphenyl and its -3-mono- and -2, 21- and -3, 31- disulphonic acids and 3, 31- dichloro- and -dimethyl- 4, 41-diamino-diphenyl. Specified compounds of formula A-R1-Y-R2-A which may contain the substituents similar to those of the diamines are 4-amino-41-acetylaminodiphenyl and its -3-sulphonic acid and 4-nitro-41-aminostilbene-2, 21-disulphonic acid. Specified pyrazolones are 3-methyl-5-pyrazolone, 1-alkyl-3-methyl-5-pyrazolone and especially 1-phenyl-3-methyl-5-pyrazolone and its 41-methyl- and -chloro-phenyl derivative and particularly 1-phenyl-5-pyrazolone-3-carboxylic acid, 1-phenyl-3-methyl-5-pyrazolone-31- and -41-sulphonic acid, 1-(41-methylphenyl)-3-methyl-5-pyrazolone-31-sulphonic acid, 1-(21-chlorophenyl)-3-methyl-5-pyrazolone-41 -sulphonic acid, 1-phenyl-3-methyl-5-pyrazolone-41-carboxylic acid, 1-phenyl-5-pyrazolone-3-carboxylic acid-31sulphonic acid and 1-phenyl-3-methyl-5-pyrazolone-31-sulphonic acid amide. Specified middle components are 1-amino-2-methoxybenzene, 1-amino-2-methoxy-5-methyl- and -ethoxy-benzene, 1-amino-2, 5-dimethoxy-and -diethoxy-benzene, 1-amino-2-ethoxy-5 1-methoxy-benzene, 1-amino-2-methoxy and-ethoxy-naphthalene and then -6- and -7-sulphonic acids. Specified end components are 2-naphthol and its 6-mono- and 3, 6-disulphonic acids, 1-naphthol-4-mono-and -3, 6- and -3, 8-disulphonic acids, 1, 8-dioxynaphthalene- 3, 6-disulphonic acid, 1-amino-5-naphthol-7- and 1-amino -8-naphthol-4-sulphonic acids, 2-amino-8-naphthol-6- and 2-amino-6-napthol-8-sulphonic acids, 2-amino-5-naphthol-7-sulphonic acid, 2-acetyl, -benzoyl-, -(41chlorobenzoyl-), -phenyl-, -(21- and 41-methoxyphenyl)-, -(31- and 41-carboxy-methoxyphenyl) -amino-5-naphthol-7-sulphonic acids, and 2 -(41-methyl- and -chloro-phenyl) and -phenyl-amino-5-naphthol-7, 31-disulphonic acids. Preferred dyestuffs are those where O-R3 is of formula <FORM:0757047/IV(c)/2> where the SO3H group is in a b -position of ring I and in which the naphthalene residue R4 contains an arylamino or acylamino group and one or two sulphonic acid groups as substituents. Dyestuffs in which R3 is a naphthalene residue, e.g. those in which R3 corresponds to a 2-methoxy-6 -sulpho-naphthalene residue, are preferably coppered with copper sulphite and an alkali acetate, and those in which R3 is an alkoxy-benzene residue, e.g. 1-methyl-4-methoxy-, 1, 4-dimethoxy- and 1-methoxy-4 diethoxy benzene are preferably treated with copper tetramine sulphates. The dyestuffs dye wool, silk and especially cellulose containing fibres, e.g. cotton, linen, artificial silk and regenerated cellulose in grey to olive green tints. Examples and a table are provided illustrating the preparation of the dyestuffs from certain of the above components and their use in dyeing cotton, additional components used to those previously mentioned are 1-phenyl-5-pyrazolone-3-carboxylic and -41-suphonic acid, 4-amino-41-oxalylamino-diphenyl, 1-benzoyl- and -acetylamino-8-naphthol-4-sulphonic acids, 2-benzoylamino-6-naphthol-8-sulphonic acid and 2-phenylamino-5-naphthol-7-sulphonic acid-31-carboxylic acid. Specifications 644,883 and 738,309 are referred to.