Speciality dyes‐new trends in modern dye chemistry

The demand for new dyes for specialised applications, i.e. applications outside the conventional polymer coloration fields, has increased dramatically in recent years, and there is a strong case to be made for the establishment of an international directory of such substances. Here some of the more important speciality dyes are reviewed. For convenience, dye applications are classified according to the relevant property of the dye chromophore that is exploited, i.e. light absorption, light emission, electrical behaviour, chemical reactivity, and photochemical reactivity.