Chemical Laboratories, Government Model Science College, Gwalior·474 002 Manuscript received 18 February 1991, revised 29 May 1991, accepted 3 September 1991 A series of new pyrazolones and esters have been synthesised. Treatment of ethyl benzoylacetate with diazotistd 2/4-aminobenzoic acid gave ethyl 2-(2/4-carboxy-phenylazo)-2-benzoylacetates. Reaction of the esters with anilinomalonic acid hydrazides gave 1-sutstituted-2-phenyl-4-(2/4-carboxyphenylazo)-5-pyrazolones. The dyes impart mostly light yellow colour of different shades on cotton, silk and wool fibres and light orange to deep brown on nylon fibres in presence of mordants. The pyrazolones were tested for their antifungal activity.