Abstract: Coumarin compounds of the general formula (1) ##STR1## in which A denotes an oxygen atom or a grouping >N--R in which R represents a hydrogen atom or an alkyl radical of 1 to 18 carbon atoms which may be substituted by fluorine, chlorine or bromine atoms or by alkoxy.sub.C.sbsb.1.sub.-C.sbsb.4, dialkyl.sub.C.sbsb.1.sub.-C.sbsb.4 -amino, --SO.sub.2 --N(alkyl.sub.C.sbsb.1.sub.-C.sbsb.4).sub.2 or cyano groups or a cycloaliphatic, aromatic or heterocyclic radical which may be substituted by fluorine, chlorine or bromine atoms or by alkyl.sub.C.sbsb.1.sub.-C.sbsb.4, alkoxy.sub.C.sbsb.1.sub.-C.sbsb.4, hydroxyl, cyano, sulfonamide or --SO.sub.2 --N--(alkyl.sub.C.sbsb.1.sub.-C.sbsb.4).sub.2 groups, X denotes an oxygen atom or a grouping .gtoreq.N--R' in which R' represents a hydrogen atom or an alkyl.sub.C.sbsb.1.sub.-C.sbsb.18 carbonyl, alkoxy.sub.C.sbsb.1.sub.-C.sbsb.4 carbonyl, alkyl.sub.C.sbsb.1.sub.-C.sbsb.4 carbamoyl or alkyl.sub.C.sbsb.1.sub.-C.sbsb.

Abstract: Mixtures of optical brighteners consisting of 5 to 95% by weight of a compound of the formula ##STR1## in which A denotes a o- or p-cyanophenyl group, and 95 to 5% by weight of one or more further optical brighteners.

Abstract: Mixtures of optical brighteners consisting of 5 to 95 parts by weight of a mixture consisting of 0 to 80% by weight of the compound of the formula 1 ##STR1## 20 to 100% by weight of the compound of the formula 2 ##STR2## and 0 to 80% by weight of the compound of the formula 3 ##STR3## and 95 to 5% by weight of one or more other optical brighteners.

Abstract: Benzimidazo-[1,2-a]-quinolines of the formula ##STR1## In the solid and dissolved state, the compounds of the invention are strongly fluorescing from reddish-blue to red, depending on the substitution. The compounds can be used as optical brighteners and as fluorescent dyestuffs. Furthermore they are valuable intermediates for the preparation of optical brighteners and fluorescing dyestuffs. They are distinguished by a very good fastness to light.