<p>This study reports the development of a 1,5-diphenylcarbazide (DPC)-functionalized starch thin film as a colorimetric sensor for chromium (VI) detection via naked-eye detection and /or UV–Vis spectrophotometer. This sensor was fabricated using a starch film as a solid support, in which DPC was embedded as a reagent. It acted as a colorimetric substrate, resulting in the formation of a pinkish-red hue in acidic conditions. The surface morphology of the colorimetric sensor was assessed using Fourier-transform infrared (FT-IR) spectroscopy, field emission scanning electron microscope (FE-SEM), and energy-dispersive X-ray (EDX) spectroscopy analytical methods. To obtain the highest extraction recovery and reliability, some of the main parameters were optimized. The film was used in conjunction with a spectrophotometer or naked eye, providing a linear range in the range of 0.15-10 mg L^− 1, with determination coefficient R² = 0.9906. The limit of detection and quantification were calculated to be 0.05 and 0.15 mg L^− 1, respectively. The obtained film was successfully applied to the identification and determination of chromium in leather samples with good recoveries.</p>