Polarized absorption and the third order nonlinear optical susceptibilities for monolayer assemblies of tetraphenylporphyrin derivatives prepared by vertical dipping(LB) and horizontal lifting(Hl)methods are determined by optical third-harmonic generation(THG) measurements at a wavelength of 1907 nm. It has been found that Y-type films prepared by LB method show larger red shift in the UV-vis absorption spectra and also give larger chi((3)) in, comparison with the X-type films prepared by HL method. This result is discussed with the difference in the electronic interaction between the porphyrin molecules in the films, induced by the transferring process.