The organic thin films of stearic acid/pyrazoline nanoparticles were prepared by transferring Langmuir monolayer of stearic acid/pyrazoline nanoparticle onto the solid substrate. The Langmuir behavior of stearic acid/pyrazoline nanoparticle complex was studied with pressure-area isotherm at the air/water interface. The prepared Langmuir-Blodgett film was identified with linearly increasing optical absorbance around 370 nm by increasing the number of deposited layers. The surface morphology of the LB film was observed with AFM. The dispersion of pyrazoline nanoparticle in the thin film was studied with TEM.