Modification of side chain of conjugated molecule for enhanced charge transfer and two-photon activity

Abstract Amounts of strategies implemented to obtain improved two-photon absorption responses but remains challenging. Herein, a serials zwitterionic chromophores, TSEO1–3, with D-π-A configuration were rational designed and synthesized. Notably, by minor modification of the side chain, the obtained TSEO3 exhibited enhanced two-photon activity and considerable two-photon imaging in vitro and in vivo. It manifested that appropriate modifications of side chains that are linked to conjugated frameworks can improve the intermolecular packing order and boost charge transfer favoring two-photon activity.