Azo dyes based on naphtholic oligomers

A series of oligomeric azo dyes has been prepared by coupling various diazo nium salts of benzothiazoles to 1-naphthol/formaldehyde (1-NF) and 2-naphth ol/formaldehyde (2-NF) oligomers. They were characterised in terms of their softening point, yield, colour, solubility and UV-VIS spectra. Structure-p roperty relationships are discussed. Dyeing on polyester, nylon-6,6, and wo ol resulted in orange to red coloration having excellent light and washing fastness properties.