Mixtures of dodecene and methyl undecylenate were employed to form mixed films on Si(I 11) surfaces. By varying the mole fraction of the solution. the surface coverage of the ester group could be controlled. Rhodamine 590 was used to label the acidified functional group, and the emission spectra showed that the emission intensity was linearly related to the composition of the binary solution. The capacitance of the film from the impedance study was found to be sensitive to the film composition. An interesting non-linear relationship between the capacitance and the mole fraction was observed, indicating a strong influence on the dielectric property of the film by the variation of the mole fraction. Based on a two-dimensional grid random statistic model, the experimental data were simulated.