2-Chloro-5-isobutyrylthiophene is made by treating 2-chlorothiophene with isobutyryl chloride in benzene in the presence of stannic chloride with subsequent decomposition of the complex thus formed and nitrated with mixed sulphuric and nitric acids to yield the corresponding 3-nitro derivative which on treatment with ammonium hydroxide in methanol yields 2 - amino - 3 - nitro - 5 - isobutyrylthiophene. 2 - Amino - 3 - nitro - 5 - acetyl -, - propionyl -, - trifluoroacetyl - and - (31,41-dichlorobenzoyl)-thiophenes are made in a similar fashion starting from the 2-chloro-5-acyl-thiophenes. 2-chlor - 5 - benzoyl -, - (21 - chlorobenzoyl)-, - (21-methoxybenzoyl - and - (21,41 - dichlorobenzoyl)-thiophenes are prepared as indicated above and nitrated to yield the corresponding 3-nitro-5-(31 - nitrobenzoyl) -, - (51 - nitro - 21 - chlorobenzoyl) -, - (51 - nitro - 21 - methoxybenzoyl) and - (21,41 - dichloro - 51 - nitrobenzoyl) - thiophenes which are converted to the corresponding 2-amino-derivatives with methanolic ammonium hydroxide. Specifications 764,296, 764,297 and 764,298, [all in Group IV (a)], are referred to.ALSO:The invention comprises azo dyes of formula <FORM:0774611/IV(b)/1> where Z is an acetyl, propionyl, iso or n-butyryl, trifluoroacetyl benzoyl or substituted benzoyl group and R is the residue of an aniline, tetrahydroquinoline or benzomorpholine coupling component. They are made by coupling appropriate azo and coupling components by conventional methods. Preferred dyestuffs are of formula <FORM:0774611/IV(b)/2> and <FORM:0774611/IV(b)/3> where R1 is H, an alkyl group of 1-4 C atoms, a hydroxyalkyl group of 2-4 C atoms, an alkoxyalkyl group of 3 or 4 C atoms, a cyanoalkyl group of 3-5 C atoms, b -acetoxy-, -carbomethoxy- and -carboethoxy-ethyl and carbomethoxy- and carboethoxymethyl groups, R2 is as R1 with the addition of b , b -difluoro-ethyl and n-propyl, g , g -difluoro-propyl and n-butyl, d , d -difluoro-n-amyl, b , b , b -trifluoro-ethyl, -propyl and -butyl groups, X is H, Br, Cl, Me, Et, MeO, EtO or acetyl-, propionyl- or n-butyryl-aminogroups, Y is H, Me, Et, MeO or EtO, Z is as above, R3 is a hydroxy alkyl group of 2-4 C atoms, Q is H or Me and Q1 and Q2 each are H, Me, MeO, Cl, Br, F, or acetyl-, propionyl- or butyrylamino groups. Specified coupling components are aniline, m-toluidine, -anisidine and -chloraniline, 2-methoxy-5-chloro-, -methoxy- and -methyl, N-b -hydroxyethyl- and -propyl-, -b , g -dihydroxypropyl, -g -hydroxy-propyl-, -d -hydroxybutyl-, -b -hydroxyethyl-o-chloro-and -methoxy-, -b -cyano-, -methoxy- and -ethoxy-, -b -carboethoxyethylm-chloro-, N, N-di-b -hydroxyethyl-, -di-b -hydroxyethyl-m-bromo- and -chloro-, N-ethyl-N-d -hydroxybutyl- and -N-(b -methyl-b , g -dihydroxypropyl)-, N-b -cyanoethyl-N-(b -sodium phosphatoethyl)-m-chloro-, N-b -hydroxyethyl-N-b , b , b -trifluoroethyl-, -g , g , g -trifluoropropyl-, -d , d , d -trifluorobutyl- and -b , b -difluoro-ethyl- and -propyl-, N-b -hydroxypropyl-N-g , g -difluoropropyl, N- b , g -dihydroxypropyl-N-g , g -difluorobutyl- and -d , d -difluoroamyl-, N-methyl-N-b -hyroxyethyl-m-bromo-, N, N -di-b -hydroxyethyl-2, 5-diethoxy- and -dichloro-, N-n-propyl-, -isopropyl- and n-butyl - N - b - hydroxyethyl -, N - b -hydroxyethyl-N-cyanoethyl-m-chloro-, N-b -hydroxyethyl-, N-g -cyanoethyl- and -b -carboethoxy ethyl-m-chloro, N-b -hydroxyethyl-N-g -cyanopropyl-, N-b -carbomethoxyethyl, N-b -carboethoxyethyl-N-b -hydroxyethyl- and -N-b -hydroxyethyl-N-b -chloroallyl- and b -nitroethyanilines, N-b -carbomethoxyethyl. N, N-di-b -hydroxyethyl-N-ethyl-N-b , g -dihydroxypropyl-, N-butyl-N-(b -sodium sulphatoethyl)-, N-methyl-N-b , g -dihydroxypropyl- and N-b -methoxyethyl-N-b , g -dihydroxypropyl-m-toluidines, tetrahydroquinoline, benzomorpholine and 1-ethyl-, -b -hydroxyethyl-, -b , g -dihydroxypropyl-, -b -methyl-b , g -dihydroxypropyl-, -g -hydroxypropyl-, -d -hydroxybutyl-, -b -hydroxyethyl-2, 7-dimethyl-, b , g -dihydroxypropyl-, 2 - methyl-, 7 - methyl-, -chloro-, -bromo- and -fluoro- and -2, 7-dimethyl-, -b -hydroxyethyl-7-ethyl- and -methoxy-, - b - methyl - b , g - dihydroxypropyl - 7 - ethoxy-, - b - methoxy - ethyl-, - ethoxyethyl, - b - cyanoethyl -, b - carbomethoxyethyl -, - b - carboethoxyethyl-, b , b , b -trifluoroethyl, -d , d , d - trifluoxobutyl - b , b - difluorethyl -, - b , b - and - g , g - difluoropropyl -,-d , d -difluoraamyl b - hydroxypropyl - 2, 7 - dimethyl-, b - sulphato - and - phosphatoethyl -, - alkyl - and b - phosphonoethyl - tetrahydroquinolines and -benzomorpholines. The dyestuffs dye wool, silk, nylon, polyethylene terephthalate textile materials, fibres made by graft polymerizing acrylonitrile cellulose and alkyl carboxylic acid esters of 2-4 C atoms, especially cellulose acetate, in blue shades. Examples illustrate the preparation of the dyestuffs and their use in dyeing process certain of the above specified components being used and many others closely corresponding thereto, the substituents in the benzoyl residue of the azo component being nitro, methoxy and chloro groups and an additional substituent in the coupling components to the substituents of those already listed being acetylamino. Specifications 764,296, 764,297 and 764,298 [all in Group IV(a)] are referred to.