reaction of furfural and diglycerol, both of which can be derived from renewable resources. The 1H and 13C NMR analyses revealed that DFDG is a mixture of stereoisomers. Diels–Alder (DA) polymerization of equimolar amounts of DFDG and 4,4′-bismaleimidodiphenylmethane (BMI) at 60 °C for 48 h in chloroform afforded a bio-based linear polyimide (DFDG–BMI) with Mw of 5400. Prolonged reaction time resulted in