A novel disperses azo dye for dyeing polyester and nylon6 fabrics in supercritical carbon dioxide fluid has been synthesized. 3-cyano acetyl indol was used as starting material and reacted with aryl/heteroaryl diazonium salts to afford arylhydrazonopropanenitriles. The newly synthesized compounds were characterizedby elemental analysis and spectral data (IR, ¹H-NMR) and the results were found to be in good agreement with the proposed structures. The influence of scCO₂working conditions such as dyeing concentration, pressure, temperature, dyeing time on fabric colour strength were studied. Moreover, the colour strength was examined in detail.In addition, the position of color in CIELAB coordinates (L*, a*, b*, H*, C*) was assessed. The color fastness of the dyed samples gave excellent results. ATR-FTIR of dyed samples were investigated and found to match with the proposed structure.