The global climate crisis, driven by unchecked industrialization and ecological negligence, compels humanity to seek alternative ways to either avert or mitigate the disastrous environmental phenomena encountered, particularly in recent years. The significant quantities of biomass generated by human activities may serve as important resources for technological applications, and biomass valorization offers dual benefits. This review emphasizes the potential of starch and lignin as adaptable materials for the advancement of sustainable and eco-friendly technologies. By investigating catalytic alterations, we may advance a more sustainable future and tackle the escalating issues of environmental pollution and sustainability. Catalytic alterations of lignin and starch have become essential techniques for their valorization. Biopolymers can be changed into useful chemicals and materials, like levulinic acid, lactic acid, 5-HMF and modified starch, which are used in the paper, textile, and coatings industries. Besides transforming into chemicals, lignin and starch can produce reactive carbon compounds that find application in both classical chemistry and photocatalysis. Additionally, we can use their highly functionalized polymeric matrices as catalysts. We can change the polymeric matrices’ chemical backbone to make them better at speeding up reactions like cross-coupling and multicomponent reactions.