Abstarct: The reaction of 4-nitrobrnzoic acid with thionyl chloride lead to the formation of 4-nitrobenzoyl chloride. 4-nitrobenzoyl azide was synthesized upon treatment of 4-nitrobenzoyl chloride with sodium azide. 4-nitrobenzoyl azide was heated in dry toluene to give 4-nitrophenyl isocyanate, which without separation was reacted with ethyl carbazate to give 1-ethoxycarbonyl-4-(4-nitrophenyl) semicarbazide. The reaction of 1-ethoxycarbonyl-4-(4-nitrophenyl) semicarbazide with 4 molar potassium hydroxide was given 4-(4-nitrophenyl) urazole. The amino group of 1-ethoxycarbonyl-4-(4-nitrophenyl) semicarbazide was reduced by tin chloride dihydrate and 1-ethoxycarbonyl-4-(4-aminophenyl) semicarbazide was formed. The reaction of 1-ethoxycarbonyl-4-(4-aminophenyl) semicarbazide with sodium ethoxide furnished 4-(4-aminophenyl) urazole. Diazotization of the amino group of 4-(4-aminophrnyl) urazole by sodium nitrate and then azo coupling with β-naphthol lead to the formatioin of 4- (4-aminophenyl) urazole → β-naphthol with high yield and purity. 4-(4-nitrophenyl) urazole was reacted with two moles of hexamethylene diisocyanate (HMDI) and isophorone diisocyanat (IPDI) in dimethylformamid (DMF) to produce new diisocyanate. The products were reacted with 4-(4-aminophenyl) urazole → β-naphthol without separation to producing novel dye copolrmers, with relatively good inherent viscosities. Reaction of 1- ethoxycarbonyl4-phenylsemicarbazide with KOH 4M lead to the formation of 4-phenyl urazole. The synthesize compound was reacted with two moles hexamethylene diisocysnate, isophorone diisocyanate and tolylene diisocyanate to produce the related new diisocyanates. The products were reacted with 4-(4-aminophenyl) urazole→ β-naphthol without separation to producing novel dye copolymers with good inherent viscosities.