Hybrid organic/inorganic heterojunction of nanocrystalline 5,10,15,20-Tetrakis(4-methoxyphenyl)-21H,23H-porphine cobalt(II), (CoMTPP) and p-Si was fabricated by using the conventional thermal evaporation technique. The morphologies of the CoMTPP/p-Si were investigated by scanning electron microscopy (SEM). The dark current–voltage (I–V) characteristics of Au/p-CoMTPP/p-Si/Al heterojunction diode measured at different temperatures ranging from 298 to 423K have been investigated. Analytical approaches involving the thermionic emission and space charge limited currents (SCLC) were used to explain the I–V behavior in the forward bias. On the other hand, the carrier generation–recombination process limits the reverse current. The dependence of capacitance–voltage (C−2–V) for the device CoMTPP/p-Si was found to be almost linear which indicates that the junction behavior is abrupt nature and then the essential junction parameters were obtained. The performance of heterojunction showed a photovoltaic behavior with an open circuit voltage, Voc, of 0.283V, short circuit photocurrent ISC, of 0.433mA and power conversion efficiency, η of 3.6%.