In this study, Mn doped complexes were produced and used as an interfacial layer in Au/Mn-complex/n-Si structure. For this aim, a mixed ligand complex was prepared and doped with manganese. The morphological investigations of these structures were fulfilled by using an Atomic Force Microscope. The analyzes showed that relatively smooth and well ordered surfaces. The fabricated devices were characterized using capacitance-voltage (C-V) and conductance-voltage (G/ w-V). The electrical parameters such as dielectric (e¢, ε″ and tanδ), electrical modulus (M′ and M″), serial resistance (Rs), interface states (Dit) and ac conductivity (σac) of fabricated Au/Mn-complex/n-Si structure were determined at various frequencies (1 kHz—1000 kHz) and voltages (−2 to 4V with steps 0.02 V), at room temperature and dark environment. Measurements have shown that capacitance and conductivity are highly frequency dependent. At low frequencies, the surface states have increased, but as the frequency increased, the values became too low to pin the Fermi level.