Miniaturized chemical sensors are desirable for field analysis and screening trials aiming at point-of-care diagnostics. For this purpose, nanostructured materials, including those of the 2D family, are highly promising once they can add to sensing devices improved properties regarding sensitivity, the limit of detection, and portability. Here we report the synthesis, characterization, and application of 2D-carbonylated graphitic carbon nitride (c-g-C3N4) in the modification of screen-printed electrodes for photoelectrochemical analysis. Morphological and structural features of the material were studied through atomic force microscopy, scanning electronic microscopy, transmission electronic microscopy, X-ray diffraction, Fourier transformed-infrared spectrophotometry, and X-ray photoelectron spectroscopy. The optical bandgap of the semiconductor was estimated using diffuse reflectance spectrophotometry. Glucose determination was performed as proof of concept using c-g-C3N4 as support for the immobilization of glucose oxidase and application of the photoelectrochemical sensor. The device presented a linear range from 0 to 5.00 mmol L− 1 and a limit of detection of 0.43 mmol L− 1 . Our results indicate the suitability of employing c-g-C3N4 for designing photoelectrochemical sensors for detecting analytes of biological and medical interest.