<p>Photo-induced reaction-diffusion systems provide a valuable theoretical framework for exploring nonequilibrium self-organization under external energy input. Most existing studies have focused on binary mixtures subjected to globally uniform driving, whereas realistic chemical and biological systems are typically multicomponent and experience strongly localized energy supply. In this work, we extend photo-induced reaction-diffusion models to a multicomponent setting and systematically investigate pattern formation in a minimal three-component system. By combining numerical simulations with linear stability analysis, we find illumination can induce periodic nonequilibrium structures, whose characteristic length scales can be tuned by the input energy density and intrinsic molecular energetic parameters. We further introduce localized illumination to capture the effects of spatially heterogeneous energy input. Under such conditions, a theoretical phase diagram for pattern formation is constructed, revealing distinct spatial morphologies, including dot patterns and target-like structures. In addition, we explicitly examine the nonnegativity of entropy production for both globally and locally illuminated systems. These results provide a unified and physically consistent framework for understanding photo-induced pattern formation in multicomponent nonequilibrium systems and are also applicable to photoexcitation-controlled supramolecular systems such as persulfurated-arene/block-copolymer assemblies.</p>