Reactive dyes of the foprmula I where is 1 or 2 is 0 or 1 y'- is vinyl or a radical of the formula C2H4Q, where Q an alkali-detachable group, Het is the radical of a 5- or 6-membered aromatic hetero'cyclic ring having from 1 to 3 hetero atoms selected from the group consisting of oxygen, sulfur and nitrogen,W is either in case 1) the radical of a coupling component, of a A monoazo dye or additionally, when b = 0, of a disazo dye, which may each bear further fiber-reactive groups, or in case 2) the radical of a chromophore which optionally has further fiber-reactive groups and is derived from an optionally metallized mono- or disazo dye, a triphen dioxazine, an anthraquinone, a metallized formazan or a metallized phthalocyanine, and Ll and L2 are each a bridge member, are useful for dyeing or printing hydroxyl-containing or nitrogenous substrates.