Active methylene compound such as ethyl acetoacetate was coupled with diazotized arylamines to give ethyl arylazoacetoacetates. When the obtained compounds refluxed with 3-hydrazinyl-4,5-diphenyl-1H-pyrazolo[3,4-c]pyridazine in the presence of ethanol yielded 1-(4, 5-Diphenyl-1H-pyrazolo[3, 4-c]pyridazin-3-yl)-3-methyl-4-(2-phenylhydrazono)-1H-pyrazol-5(4H)-one derivatives. The dyes were applied to polyester fabric, and their absorption spectral characteristics, fastness properties and color assessment measured.