Absorption, Fluorescence, and Two-Photon Excitation Ability of 5-Phenylisolidolo[2,1-]quinolines.

We report on the absorption, fluorescence, and two-photon excitation spectra of a series of 5-phenylisoindolo[2,1-]quinoline dyes. Depending on the substituents, we observed increasing two-photon absorption cross sections, with values up to 56 GM@973 nm, which are similar to those of the enhanced green fluorescent protein and fluorescein, common fluorescent chromophores.