The thin organic films based on 4,4'-bis-[(Z)-1-(1,3-benzoxazol-2-yl-2-ethenyl)]biphenyl and its partly fluorinated derivatives are studied. Absorption, luminescence, and excitation spectra, luminescence decay and film morphology were found to depend sensitively on the changes in molecule structure, nature and temperature of the substrate, as well as the thermovacuum deposition rate, being the origins of bad reproducibility of the optical properties of such films. Molecular aggregation with chromophore dipoles arranged parallel to each other has been observed in absorption and luminescence spectra. The fluorescence characteristics can be explained by the combination of radiation of aggregated and non-aggregated molecules. The main characteristics of the molecules under study are calculated using DFT approach. The unusual behaviour of photodegradation in fluorinated film is found.
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