Hexyltriphenylphosphonium-TCNQ(HTPP-TCNQ) complex for preparing organic thin film by Langmuir-Blodgett technique was synthesized from LiTCNQ and Hexyltriphenylphosphonium bromide. The structure of the new complex was confirmed by $^{1}H$ NMR, $^{31}P$ NMR, IR, UV spectroscopies, TGA and elemental analysis. A stability to spreading solvent, which is acetonitrile, ethylacetate, ethanol and acetonitrile-ethylacetate(1:1 v/v), of HTPP-TCNQ complex was investigated by UV-visible spectrophotometer. The complex was stabilized in acetonitrile, ethylacetate, aceton, acetonitrile-ethylacetate (1:1 v/v) for 6 h.