Electron donor-acceptor compounds of optically pure covalently linked Zn(II)-pyropheophytin-anthraquinone (ZnPQ) have been synthesized. These compounds allow one to prepare highly ordered solid samples by means of the Langmuir-Blodgett technique. Monolayer films of the P4(S)-ZnPQ diastereoisomer were prepared in a dioleoyl phosphatidylcholine matrix with the concentration varied from 0.5 to 10 mol.%. The time-resolved fluorescence properties of the films were interpreted in terms of the presence of two types of P4(S)-ZnPQ conformers, the folded one and the opened one. The folded conformer predominated and underwent fast intramolecular electron transfer (rate constant > 10(11) s(-1)) from the Zn-pyropheophytin part to the anthraquinone moiety and was, therefore, not observed directly in the fluorescence study. The open conformer had a relatively long-lived singlet excited state and was quenched by an energy transfer process to the folded conformer at P4(S)-ZnPQ concentrations higher than 2 mol.% with an estimated quenching radius of 5 +/- 0.2 nm.