Abstract: There are described novel dyes of the formulae ##STR1## in which R.sub.1 and R.sub.2 independently of one another are each hydrogen, unsubstituted or substituted alkyl, cycloalkyl, aralkyl or aryl, and R.sub.1 and R.sub.2 together with the nitrogen atom, and optionally with the inclusion of further hetero atoms, can also form a 5- to 7-membered heterocycle, or one of the radicals R.sub.1 or R.sub.2 can be linked with the carbon atom, in the o-position with respect to the amino group, of the ring A to form a fused-on, saturated, unsubstituted or substituted 5- or 6-membered ring,X is .dbd.NR.sub.3, .dbd.NCOR.sub.4, ##STR2## .dbd.NH or .dbd.O, wherein R.sub.3 is alkyl or unsubstituted or substituted phenyl,R.sub.4 is unsubstituted or substituted alkyl, aralkyl, aryl, vinyl, alkoxy, phenoxy or amino, andR.sub.5 is cyano, carbalkoxy, or unsubstituted or substituted carbonamide, andR.sub.

Abstract: The invention relates to novel 4-styryl-4'-vinylbiphenyls of the formula ##STR1## wherein the benzene rings A, B and C can carry non-chromophoric substituents and R.sub.3 is a second order non-chromophoric substituent, and R.sub.4 is hydrogen or a non-chromophoric substituent which cannot be a second order substituent, and also a process for obtaining them. These novel compounds can be used as fluorescent whitening agents for treating organic material of high molecular weight, preferably textile material, most preferably polyester fibres. The invention also discloses novel intermediates of the formula ##STR2## wherein A, B and C are as defined above, which are formed during the production of the novel 4-styryl-4'-vinylbiphenyls, and also a process for obtaining them.