Bioplastics are indispensable for establishment of green-sustainable society. Conventional bioplastics composed of aliphatic polymers like poly(lactic acid)s are successfully circulated as a specific field. In order to widen the field of bioplastics, aromatic bio-based polymers are required. Under this background, we have prepared aromatic biopolymers derived from exotic biochemicals with rigid backbones [1-3]. Here we used 4-aminocinnamic acid (4ACA) which was bioavailable by a microorganismal genetic-engineering. The photodimer of 4ACA was successively prepared as a bio-derived aromatic diamine via [2+2] cycloaddition in the solid state with a perfect conversion degree by illumination of UV-LED. The biodianilines were polymerized with diisocyanates, diacids, and tetraacid dianhydrides to produce aromatic polymers such as polyureas, polyamides, and polyimides, respectively. Almost bio-based polymers prepared here showed a high transparency, high heat-resistance, and high mechanical strength. Especially the biopolyamide showed extremely-high fracture strength around 400 MPa as high as those of high-tensile steels, in spite of amorphous structure [3]. The optimization of the biopolyimide structure gave the fantastic properties of ultrahigh toughness comparable with those of spider silks. On the other hand, the aromatic polyimides derived from the bio-photodimer with cyclobutanetetracarboxylic dianhydrides showed a good thermomechanical performance as well as low density around 1.05-1.28 g/cm3, and additionally showed a high transparency [2,4]. These thermal/mechanical performances are higher than those of conventional transparent polymers, in spite of limited molecular design by bio-based molecules. Additionally we found that the water-solubility was imparted in polyimide materials when the side carboxylate groups were ionized, which was a surprizing phenomenon because the aromatic polyimides are generally insoluble in any solvents. Acknowledgement: The authors gratefully acknowledges Grant-in-Aid supports from ALCA (5100270) of JST, Japan and from Scientific Research (B) (15H03864) of MEXT, Japan.