To explore and expand the chemical space of natural products, there is an urgent need for efficient and functional modification of natural products. Here, a photoinduced strategy is reported to access flavanone-based pseudonatural products via late-stage functionalization. This mild procedure enables the chemical evolution of diverse flavanones via introduction of 1,1-diarylalkane scaffolds. The method features mild reaction conditions, operational simplicity, high functional group tolerance, and scalability. Moreover, the cheminformatics results indicate that the pseudonatural products possess excellent drug-like properties and shape diversity. Finally, the catechol-O-methyltransferase (COMT) inhibitory activity analysis demonstrated that compounds 26d and 28d exhibit potent COMT inhibition, with IC50 values of 85.2 and 99.7 nM, respectively, providing valuable insights for the development of novel flavanone-based non-nitrocatechol COMT inhibitors for Parkinson’s disease treatment.