Abstract: Water-soluble azo dyes of the formula ##STR1## in which R.sub.1 signifies an aromatic or heterocyclic radical which may be substituted,R.sub.2 has one of the significances of 1 or is the radical of a coupling component, for example, a radical of a coupling component bearing an active methylene group,And the molecule contains 1 or 2 sulfo groups,And the ring A may be further substituted,And processes for their synthesis. These dyes are useful for the dyeing and printing of a variety of organic materials including natural and synthetic polyamide fibers, e.g., wool, and paper. The obtained dyeings and prints exhibit good fastness to light and wet treatments as well as to gas fumes and rubbing, and dyeings obtained in combination with blue dyes, for example blue cationic anthraquinone dyes, exhibit good resistance to catalytic fading.

Abstract: Water-soluble nitro compounds of the formula ##SPC1##Where R.sub.1 and R.sub.2, independently of each other, represent aromatic or heterocyclic radicals which may be substituted,R.sub.3 an aromatic or heterocyclic radical which may be substituted,And the molecule bears 1 or 2 sulphonic acid groups are valuable dyes especially for synthetic polyamide fibers.