Brilliant green (BG) dye material-based heterojunction is fabricated by a spin coating route and characterized by impedance analyzer. Here, we study the impedance spectroscopy of such organic material based thin film onto silicon substrate. The capacitance and conductance versus voltage (C-V), (G-V) characteristics are plotted. So, the dielectric response of BG based heterojunction is studied via the plotting of the dielectric constant, modulus components, complex impedance and Nyquist diagram. Real and imaginary parts of electrical conductivity are also plotted at several frequencies. Real and imaginary parts of electric modulus M’-V and M”-V are investigated for all experimental frequencies. The Z’-V characteristics of our device-based BG organic heterojunction exhibit a peak of 1383 W. It is confirmed that an anomalous peak of Z’ is recorded within 0.5-1 V range. The drastic decay in Z”-V plot occurs for lower 100 and 200 kHz frequency range and Z” values become constant beyond 1V for all frequencies. Ac and Dc conductivity curves demonstrate a growth with frequency and angle phase approaches to 90º within reverse voltage. This result reveals a capacitive conduct of our device.