Abstract: Benzodifuranes of the formula ##STR1## wherein R represents hydrogen, alkyl or halogen, each of R.sub.1, R.sub.2 and R.sub.3 represents hydrogen or different non-chromophoric substituents, with the proviso that at least one of the symbols R, R.sub.1, R.sub.2 or R.sub.3 does not represent hydrogen, processes for their production and the use thereof for whitening organic material of high molecular weight, especially polyester, polyvinyl chloride or polystyrene.

Abstract: Novel benzoxazole compounds of the formula ##STR1## wherein R.sub.1, R.sub.2 and A are certain substituents, a process for their manufacture as well as their use as optical brighteners are disclosed.

Abstract: The invention is directed to new benzoxazole-styryls of the formula ##STR1## wherein the rings A, B, C and D can be substituted, as well as processes for their preparation. The invention relates also to a process for optically brightening high-molecular organic materials on using said compounds.

Abstract: Stilbene compounds of the formula ##STR1## wherein R denotes the radical ##STR2## and wherein the rings A, B, C, D and E can carry non-chromophoric substituents are useful for the optical brightening of organic materials.

Abstract: Process for the manufacture of styrene compounds of the formula ##STR1## wherein A denotes one of the ring systems ##STR2## and wherein R.sub.1 denotes hydrogen, alkyl with 1 to 8 carbon atoms, cyclohexyl, phenylalkyl with 1 to 3 carbon atoms in the alkyl part, phenyl, alkoxy with 1 to 4 carbon atoms, or chlorine, or, conjointly with R.sub.2, denotes alkylene with 3 or 4 carbon atoms, R.sub.2 denotes hydrogen or alkyl with 1 to 4 carbon atoms or, conjointly with R.sub.1, denotes alkylene with 3 or 4 carbon atoms, R.sub.3 denotes hydrogen or methyl, R.sub.4 denotes hydrogen, m-methyl, alkyl with 2 to 8 carbon atoms, phenyl, alkoxy with 1 to 4 carbon atoms, or chlorine, or, conjointly with R.sub.5, denotes a fused benzene ring, R.sub.5 denotes hydrogen or chlorine or, conjointly with R.sub.4, denotes a fused benzene ring, X.sub.1 denotes hydrogen, alkyl with 2 to 4 carbon atoms, alkoxy with 1 to 4 carbon atoms or chlorine, X.sub.

Abstract: Styrene compounds of the formula ##STR1## wherein Q denotes one of the ring systems of the formulae ##STR2## wherein M represents oxygen or sulphur, Z represents hydrogen, lower alkyl or phenyl and n represents the number 1 or 2 and the rings A and B can each contain 1 to 3 non-chromophoric substituents.

Abstract: New distyryl compounds of the formula ##STR1## WHEREIN R.sub.x denotes an optionally modified sulphonic acid group, a sulphone group, an optionally functionally modified carboxylic acid group or the nitrile group, R.sub.x ' denotes an optionally functionally modified sulphonic acid group, a sulphone group, an optionally functionally modified carboxylic acid group, the nitrile group, alkyl, alkoxy, chlorine or hydrogen, and R.sub.y and R.sub.y ', independently of one another, denote hydrogen, the sulphonic acid group or a salt thereof, chlorine, alkyl or alkoxy; these compounds are particularly useful as optical brighteners.

Abstract: Stilbene compounds of the formula ##STR1## wherein Q denotes the 1,3,4-oxadiazol-2,5-ylene or 1,2,4-oxadiazol-3,5-ylene radical and Q.sub.1 denotes one of the radicals ##STR2## and the rings A, B, C, D and E can each contain 1 to 3 non-chromophoric substituents.