Al/Zn-complex/p-Si/Al metal-polymer-semiconductor (MPS) diode is deposited by using thermal evaporation technique for metal layers and spin-coating technique for polymer interface layer. Zn(C6H6N2O)2(C6H4NO2)2(H2O)].1/2(H2O) is prepared as a precursor material and different spin-coating solutions in terms of Zn-complex contribution (0.5, 1.0, 2.0 and 3.0 mg) are used in the film deposition process. The characterization of this precursor is provided by TEM imaging. In addition, deposited interface layers in different amount of Zn-complex in solution are investigated by AFM. Current-voltage (I−V), capacitance-voltage (C−V) and conductance-voltage (G−V) characteristics of the MPS diode are evaluated as a function of compositional change at the interface under dark and illumination conditions. Main diode parameters as barrier height, ideality factor and parasitic resistances are extracted from dark I−V curves and also they are discussed for the measurements under different illumination intensity. Capacitive behavior of these MPS diodes are observed by dark C−V and G−V measurements, and resistance values are also calculated from these results. The on/off illumination switching response of the diodes are observed from transient photo-current, photo-capacitance and photo-conductance plots.