The invention provides a process for the production of azodyes and their derivatives by diazotization and coupling reactions and optionally further modification reactions, wherein a compound of formula ##STR1## in which E signifies an aromatic bivalent radical,X.sub.1 signifies hydroxy or a primary amino group,Y.sub.1 signifies hydroxy or a primary amino group and in which the aminogroup linked to the --SO.sub.2 --bound phenyl radical may optionally be acylated,or a mixture of compounds of formula (I), is employed as a coupling component or/and--in the non-acylated form--as a diazo component, the invention in particular relates also to the novel dyes and their use and to the novel intermediates.