We designed and synthesized a NLO chromophore adopting the concept of shape modification as well as possessing high thermal stability. The chromophore was featured by a phenylene ring as a conjugation bridge, a bulky alkyl chain attached on the side of the conjugation bridge, and julolidine moiety as an electron donor. The NLO chromophore was attached to the polyimide as a side chain, resulting in thermally durable NLO polymers. On ...