Abstract: In this paper, a new field of organic photochemical reaction in solid state with an important significance and characteristics is reviewed;We have investigated bimolecular photoreactions between two different organic molecules, such as a series of tryptophans and the nucleic acid beses with fused polycyclic aromatic hydrocarbons.The result shows that the reactions exhibit a high stereo-and regio-selectivity.This is a new effective synthetic method.The reaction mechnism was also postulated.By using a crystal lattice-controlling substance a series of compounds for which the photoreaction can not take place may undergo the regio-and stereo-selectivity photoreaction.The method can be employed to synthesize optical active Dor Lcompounds which need not resolution.The charge transfer(C-T)complexes and molecular compounds were also investigated in solid state photoreaction.

Key words: Solid state photochemistry, Mixed crystal, Micro-environmental influence, Two different molecules