Dipicolinate as acceptor in D–π–A chromophores: synthesis, characterization and fluorescence following single- and two-photon excitation

Three novel donor–π–acceptor type compounds with dipicolinate as acceptor have been synthesized. Their absorption, photoluminescence as well as their two-photon absorption properties have been investigated. Two of them show strong two-photon absorption and two-photon excited up-conversion fluorescence.