Two novel bio-based diamines are synthesized through introduction of renewable 2,5-furandicarboxylic acid (2,5-FDCA), and the corresponding aromatic polyimides (PIs) are then prepared by these diamines with commercially available aromatic dianhydrides via two-step polycondensation. The partially bio-based PIs possess high glass transition temperatures (T(g)s) in the range from 266 to 364 degrees C, high thermal stability of 5% weight loss temperatures (T(5%)s) over 420 degrees C in nitrogen and outstanding mechanical properties with tensile strengths of 79-138 MPa, tensile moduli of 2.5-5.4 GPa, and elongations at break of 3.0-12.3%. Some colorless PI films (PI-1-b and PI-1-c) with the transmittances at 450 nm over 85% are prepared. The overall properties of 2,5-FDCA-based PIs are comparable with petroleum-based PI derived from isophthalic acid, displaying the potential for development of innovative bio-based materials. (c) 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018, 56, 1058-1066