The present invention is directed towards a betaine-type monoazo dye for dying and printing fibrous materials, represented by formula (I):Dye--X--Y (I)wherein Dye represents a cyan dye anion represented by formula (II);X represents a bond or linking group;Y represents quaternary ammonium; andDye and X are bonded to each other via A, B.sup.1, B.sup.2, B.sup.3, B.sup.4 or B.sup.5 in formula (II): ##STR1## wherein B.sup.1, B.sup.2, B.sup.3, B.sup.4 and B.sup.5 are the same or different, and each represents a member selected from the group consisting of a bond, hydrogen, alkyl, halogen, --OR.sup.4, --CO.sub.2 R.sup.4, ##STR2## wherein R.sup.4 and R.sup.5 are the same or different and each represents a member selected from the group consisting of hydrogen, alkyl and aryl, or R.sup.4 and R.sup.5 are taken together to form 5- or 6-membered heterocyclic ring containing oxygen, nitrogen, sulfur or combinations thereof as heteroatoms;A represents a member selected from the group consisting of hydrogen, alkyl, aryl, cycloalkyl, a 5- or 6-membered heterocyclic ring containing oxygen, nitrogen, sulfur or combinations thereof as heteroatoms and ##STR3## wherein A.sup.2 and A.sup.3 have the same meaning as A, or A.sup.2 and A.sup.3 are bonded to each other to form a 5- or 6-membered heterocyclic ring containing oxygen, nitrogen, sulfur or combinations thereof as heteroatoms;E represents a member selected from the group consisting of hydrogen, halogen, cyano, hydroxyl, carboxyl, alkyl, aryl, a 5- or 6-membered heterocyclic ring containing oxygen, nitrogen, sulfur or combinations thereof as heteroatoms, alkoxy, aryloxy, alkylthio, arylthio, carbacylamino, sulfonylamino, carbamoyl, amino, alkylsulfonyl and phenylsulfonyl;G represents a member selected from the group consisting of cyano, alkylsulfonyl and phenylsulfonyl;J represents a member selected from the group consisting of hydrogen, halogen, cyano, alkylsulfonyl and phenylsulfonyl; andR.sup.1 represents a member selected from the group consisting of hydrogen and alkyl.