Synthetic phenolic antioxidants are widely used to prevent oxidative degradation in materials but often rely on non-renewable feedstocks and pose potential health risks. Researchers have now developed sustainable alternatives: novel arylindane diols sourced from lignin. The study focuses on diisoeugenol (DiE) and diisoallylsyringol (DiAS), which were synthesised selectively from the lignin-derived monomer isoeugenol via zeolite catalysis. Oxidation onset temperature (OOT) measurements in polypropylene formulations showed improved thermal stability, matching or surpassing that of commercial antioxidants. These findings suggest DiE and DiAS could serve as effective, renewable and safer alternatives for industrial antioxidant use.