Disclosed are azo dyes of the formula ##STR1## wherein R.sub.1 is an aliphatic or aryl group,R.sub.2 is cyano, alkoxycarbonyl or substituted alkoxycarbonyl,R.sub.3 is an aliphatic or aryl group, andK is a coupling component radical,The synthesis thereof and the use thereof for the dyeing and printing of textile and non-textile substrates. The disclosed disperse dyes are useful for dyeing and printing synthetic and semi-synthetic, hydrophobic, high molecular weight materials such as linear aromatic polyesters, polyamides, cellulose 21/2 acetate and cellulose triacetate. The obtained dyeings have satisfactory fastness properties, particularly fastness to light, thermofixation, sublimation and pleating.