Synthesis of maleilated polyflavonoids and lignin as functional bio-based building-blocks

•Polyflavonoids and lignin from residual biomass was modified with maleic anhydride.•The solvent, and the catalyst affect significantly the maleilation of polyphenols.•Non water soluble polyflavonoids-, and lignin-derivatives show the highest yields.•Spectroscopy methods provide valuable insights regarding the esterification extent.•Acidic solvent and highest charge of alkaline catalyst promote the best esterification efficiency.