<p>Thin-film photocatalysts have garnered significant attention in environmental remediation. Their ease of recovery, reusability, and the ability to maintain high photocatalytic efficiency while minimizing secondary pollution make them attractive. Incorporating graphitic carbon nitride (CN) on polymer-based substrates, such as polyvinylidene fluoride (PVDF) and polystyrene (PS), shows promise for thin-film-driven photocatalytic removal systems. In this study, the two polymer matrices were comparatively evaluated for the first time in CN-based catalytic film fabrication. We focused on their structural and morphological features and their impact on photocatalytic performance. The CN-including PVDF (PVDF@CN) and PS (PS@CN) thin film photocatalysts were used for tetracycline (TC) degradation under visible light irradiation. They were characterized using scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT-IR), thermogravimetric/dynamic thermal analyses (TG-DTG) and UV–visible diffusion spectra (UV–Vis DRS). The photo-degradation of TC achieved 56.5% for PVDF@CN and 71.1% for PS@CN. The degradation rate constants followed the order: PS@CN (0.0058&#xa0;min⁻¹) and PVDF@CN (0.0053&#xa0;min⁻¹). The films showed sufficient catalytic performance over a wide pH range of 6.0–12.0. However, removal rates declined in a natural water environment. Furthermore, the polymer/CN/Vis systems were mainly driven by the photogenerated holes and superoxide radicals in the presence of PVDF and PS. The polymer-based CN films demonstrated considerable efficiency in dye decomposition systems. The outcomes indicate that the as-fabricated active thin films could be efficiently utilized for industrial photocatalytic removal processes.</p>