In this study, flexible and transparent polyimide–nanocrystalline-titania hybrid optical films with a high titania content (up to 50 wt%) and thickness (15 μm) were prepared from new soluble poly (o-hydroxy-imide) s and fabricated for a three-layer antireflection coating. The hydroxyl groups on the backbone of the polyimides could provide a reaction site for organic– inorganic bonding and resulted in homogeneous hybrid solutions by controlling the mole ...