SULFO GROUP-CONTAINING MONOAZO COMPOUNDS HAVING AN UNSUBSTITUTED OR SUBSTITUTED 4-(BENZOTHIAZOL-2'-YL) PHENYL OR 4-[6'-(BENZOTHIAZOL-2"- YL)-BENZOTHIAZOL-2'-YL] PHENYL DIAZO COMPONENT RADICAL AND A 6- HYDROXYPYRID-2-ONE COUPLING COMPONENT RADICAL

Compounds of the formula ##STR1## in free acid or salt form and internal, external and acid addition salts thereof, wherein PA0 K is ##STR2## wherein R.sub.3 -R.sub.5, R.sub.20, R.sub.21 and X-Z are as defined in the specification, PA0 each of Q.sub.1 and Q.sub.2 is independently hydrogen or --SO.sub.3 M.sub.1, PA0 each R.sub.1 and R.sub.2 is independently hydrogen, C.sub.1-4 alkyl, C.sub.1-4 alkoxy or --COOM, and PA0 n is 0 or 1, wherein each M and M.sub.1 is independently hydrogen or a nonchromophoric cation, with the provisos that (i) the compound contains at least one --SO.sub.3 M or --SO.sub.3 M.sub.1 group, (ii) when K is a gruop of Formula (a), at least one of R.sub.4 and R.sub.5 is hydrogen, (iii) the total number of anionic groups equals or exceeds the total number of basic and cationic groups, (iv) the positive charge of each cationic group is balanced by the negative charge of an --SO.sub.3.sup..crclbar. or --COO.sup..crclbar. group of the molecule or of an external nonchromophoric anion, (v) when, simultaneously (1) at least one of Q.sub.1 and Q.sub.2 is --SO.sub.3 M.sub.1, and R.sub.2 is other than --COOM, and (2) K is a group of Formula (b) wherein Y is O or S, then at least one M.sub.1 is a quaternary ammonium cation, (vi) when, simultaneously (1) Q.sub.1 is 7-SO.sub.3 M.sub.1, Q.sub.2 is hydrogen, each R.sub.1 is hydrogen, R.sub.2 is methyl, and n is 0, and (2) K is a group of Formula (b) wherein each of R.sub.20 and R.sub.21 is hydrogen, and Y is .dbd.NH, then M.sub.1 is other than hydrogen and sodium, and (vii) when, simultaneously (1) Q.sub.1 is 7-SO.sub.3 M.sub.1, Q.sub.2 is hydrogen, each R.sub.1 is hydrogen, R.sub.2 is methyl, and n is 0, and (2) K is a group of Formula (b) wherein each of R.sub.20 and R.sub.21 is hydrogen, X is O, Y is .dbd.N--CN or .dbd.N--CONH.sub.2, and Z is --OH, then M.sub.1 is a quaternary ammonium cation, are dyes for hydroxy group- and nitrogen-containing organic substrates, for example, textiles consisting of or comprising a cellulosic material, leather and paper. They are employed as such or in the form of solid or, preferably aqueous liquid dye compositions.