The escalating accumulation of plastic waste in landfills and marine environments has become a pressing concern to society. Among all plastic-based waste, polystyrenes are widely utilized as a commodity plastic and present very low recyclability. To improve this scenario, photocatalysis has recently become one of the viable techniques which can be performed under mild conditions. In this concise review, we have highlighted recent advancements in the valorization of polystyrene-based plastic waste by mainly focusing on the selective functionalization of the C–H bonds. This strategy clearly holds strong promise for the sustainable and efficient conversion of polystyrene-based waste and contributes to the reduction of waste and resource conservation.