In this work, new hydrazonopropanenitrile dyes with potential antibacterial activity were applied for dyeing polyester fabrics with supercritical carbon dioxide as a dyeing medium. The experimental conditions were optimized to obtain both visibly and spectrophotometrically uniform dye uptakes in the fabric. Raman microspectroscopy firmly indicated the dye uptake through all layers of the fabric. The color strength of the fabric was evaluated by K/S measurements and proved to be higher than those of conventional dyeing. The fastness properties of the dyed fabric were evaluated and found to give excellent results. The antibacterial test was performed according to the AA-TCC method, and the results were recorded.