The authors investigated the influence on the properties of vacuum-deposited thin films of organic dyes prepared during application of magnetic fields. In spite of weak magnetic field intensity (0.1-0.3 T), the effect of the magnetic field could be observed in the PL spectra and IR-RAS spectra for 10,10 ' -bianthrone (BA) thin films. BA molecules in a vacuum-deposited thin film are oriented comparatively randomly; they are found to be oriented as perpendicular and parallel molecular planes to the substrate in the presence of the perpendicular and parallel magnetic fields, respectively. The magnetic orientation is effective for facilitating the orientation of organic low-molecular-weight molecules with high coplanarity.