Monomethine dyestuffs

Monomethine dyestuff of the formula ##STR68## wherein T.sup.1 and T.sup.2 independently of one another are unsubstituted C.sub.1 -C.sub.5 -alkyl uninterrupted or interrupted by --O--;

• C.sub.1 -C.sub.4 -alkyl monosubstituted or disubstituted by hydroxyl or chlorine;
• C.sub.1 -C.sub.4 alkyl monosubstituted by bromine, nitrile, C.sub.1 -C.sub.4 -alkoxycarbonyl, aminocarbonyl, phenoxy, benzyloxy, cyclohexyloxy, cyclohexyl, C.sub.1 -C.sub.4 -alkoxycarbonyloxy, C.sub.1 -C.sub.4 -alkylcarbonyloxy, acetylamino, C.sub.1 -C.sub.4 -alkylsulphonylamino, aminocarbonyloxy, di-(C.sub.1 -C.sub.4 -alkyl) amino, carboxyl or sulpho;
• cyclohexyl;
• phenyl-C.sub.1 -C.sub.3 -alkyl;
• hydrogen;
• C.sub.1 -C.sub.4 -alkyl uninterrupted or interrupted by --O-- and substituted by benzyloxycarbonyl, phenoxycarbonyl, phenoxy substituted by 1-5 chlorine atoms, C.sub.1 -C.sub.4 -alkylsulphonyl, benzylsulphonyl, phenylsulphonyl, benzylcarbonyloxy, benzoyloxy, C.sub.1 -C.sub.4 -alkoxycarbonyl-benzoyloxy, phenoxycarbonyloxy, tri-(C.sub.1 -C.sub.4 -alkyl) ammonium, benzoylamino, phenylaminocarbonylamino, phenylsulphonylamino or toluenesulphonylamino;
• or ethylene or 1,3-propylene unsubstituted or substituted with C.sub.1 -C.sub.3 -alkyl and connected to the 6- or 8-position of the coumarin ring;
• T.sup.3 is hydrogen or methyl;
• Q' is CN or COOR;
• R is C.sub.1 -C.sub.6 -alkyl;
• C.sub.1 -C.sub.4 -alkyl substituted by hydroxyl, C.sub.1 -C.sub.4 -alkoxy, nitrile, chlorine, bromine, benzyloxy, phenoxy, cyclohexyloxy, di-(C.sub.1 -C.sub.4 -alkyl)amino, N-tri-(C.sub.1 -C.sub.4 -alkyl) ammonium, or phenyl;
• or is allyl, cyclohexyl or phenyl;
• and
• the ring A' is unsubstituted or substituted by methoxy, methyl or chloromethyl.