Disperse monoazo dyestuffs, free from carboxylic and sulphonic acid groups, derived from 3,5-dinitro-2-amino thiophene as disazo component and an arylamine coupling component exhibit superior properties when used to give colorations to textile materials such as secondary cellulose acetate and cellulose triacetate, polyamide and aromatic polyester textile materials, said colorations having excellent fastness to light and to wet and dry heat treatments. The dyestuffs also have high tinctorial strength and excellent dyeing and build-up properties and produce depths of shade which are relatively independent of the dyebath pH, or the temperature of the dyebath or the liquor ratio of the dyebath.