This work aimed to investigate structurally defined biobased polymers as non-leachable and non-toxic UV blockers for sunscreen applications. Two dicarboxylate monomers were synthesized using two lignin-based monomeric aromatic compounds, vanillin and 4-hydroxybenzaldehyde. These two monomers were then polymerized together with linear aliphatic diols of varying lengths to produce UV-active polyesters. The structural, molecular and thermal properties of the resulting polyesters were confirmed by NMR, FTIR, HRMS, GPC, TGA and DSC analyses. These obtained polyesters exhibited high UV-visible absorption in both solutions and creams. Furthermore, the blend creams showed negligible leaching into fresh or salt water after 24 h. Finally, these obtained polyesters were nontoxic to human MG- 63 osteoblasts at concentrations up to 100 mu M. Our findings indicated the potential of this new class of structurally defined biobased polymers as efficient non- leachable UV blockers in sunscreens.