The long-range orientational order of 4-n-pentylphenylthio-4'-n-decyloxybenzoate ((10) over bar S5) doped with a dichroic dye was studied as a function of temperature in the nematic, smectic A, smectic C and smectic J phases by means of two optical spectroscopy methods: dichroism. of absorption in the visible spectral region. and fluorescence depolarization. On, the basis of absorption and. fluorescence spectra the order parameters < P(2)> and < P(4)> as well as the orientational distribution, function were determined. The discontinuous change of both < P(2)> and < P(4)> parameters at the smectic A - nematic phase transition for dye/(10) over bar S5 inixtures was observed, in an agreement with the microscopic theory proposed by McMillan. An influence of the dye molecular structure on the orientational order of the dye/(10) over bar S5 mixture was observed. The correlation between the order parameter values and the shift of the phase transitions temperatures due to the dye addition was confirmed.