A series of Oligomenc azo dyes has been prepared by coupling various diazonium salt of Benzothiazols to Resorcinol-formaldehyde(RF) oligomer. They were evaluated in terms of their softening pointes, yield, colour, solubility and U.V.-Visble spectra. Structure property relationships are discussed and dyeing on polyester PET, Nylon-6,6 and wool assessed. Dyeing on polyester, Nylon-6,6 and wool resulted in yellow, Orange and brown to red colourations having excellent fastness to light and washing.