摘要:
Mixed crystals of dyestuffs of the formula I ##STR1## wherein R denotes alkyl andn denotes a number from 2 to 4, and dyestuffs of the formula II ##STR2## wherein R.sub.1, R.sub.2 and R.sub.3 denote alkyl, with a characteristic X-ray diffraction diagram are distinguished by a high tinctorial strength and liquor stability when they are used for dyeing polyester fibres.