The EPR spectra of the hydrated electron e(aq)(-), the benzophenone radical anion, and aryl radicals could be detected in the laser photolysis of aqueous solutions of 3,3’,4,4’-benzophenonetetracarboxylic acid on a nanosecond and microsecond time scale by means of Fourier transform electron paramagnetic resonance (FT-EPR). All spectra were emissively spin-polarized by the CIDEP triplet mechanism. The hydrated electrons and the radicals were generated by photoionization of 3,3’,4,4’-benzophenonetetracarboxylic acid in the lowest triplet state (biphotonic mechanism). The hydrated electrons e(aq)(-) disappeared via fast recombination with the geminate radical cation and by attachment to ground state 3,3’,4,4’-benzophenonetetracarboxylic acid to form the ketyl radical anion. The aryl radicals were generated in a CO2 elimination reaction from the benzophenonecarboxylic acid radical cation.