The photophysical and photochemical properties of two anthryl-labeled polyimides have been studied by absorption and fluorescence spectroscopy, single-photon counting, and picosecond transient absorption measurements. The observed emission decay is triexponential, with a very short-lived component of similar to 50 ps being attributed to electron-transfer quenching by the polyimide backbone, a slower component of similar to 2 ns assigned to excimer quenching, and a second long-lived component of similar to 10 ns assigned to isolated anthryl chromophore emission. An anthryl cation radical is produced by flash excitation of the pendent anthryl chromophores. Irradiation of thin films of the anthryl-labeled polyimides at 350 nm in air results in the disappearance of the anthryl absorption bands and produces extensively photo-cross-linked polyimide thin films. Several possible photochemical reactions that might account for the disappearance of the anthryl absorption bands and subsequent photo-cross-linking are proposed.