We have reported a detailed investigation of frequency dependent properties of the Au/perylene-monoimide (PMI)/n-Si Schottky diodes in this study. Schottky diodes based on PMI have been fabricated by spin coating method. The capacitance-voltage (C-V) and conductance-voltage (G-V) characteristics have been measured in the frequency range from 30 kHz to 1 MHz at room temperature. The values of measured capacitance Cm and conductance Gm under both reverse and forward bias have been corrected for the effect of series resistance to obtain the real diode capacitance and the conductance values. The density of interface states (Dit) distribution profiles as a function of frequency has been extracted from the corrected C-V and G-V measurements. Interface trap states of the PMI/n-Si Schottky device have decreased by increasing the applied frequency and were found to be 8.13×1011 and 1.75×1011 eV-1 cm-2 for 30 kHz and 1 MHz, respectively. © 2013 Elsevier Ltd. All rights reserved.