Bisazo based on hydroxynaphthalene

The invention relates to bisazo compounds of formula (Ia) or (Ib) wherein R represents hydrogen or methyl; the groups X independently represent -CH2CH2- or -CH2CH2CH2-; R , R , R independently represent hydrogen or methyl; A represents an anion; and n represents the valency of A. The invention also relates to the use of said bisazo compounds for dyeing, especially paper, and to dyes containing bisazo compounds.