Tetraphenylporphyrin, TPP, thin films have been prepared by thermal evaporation technique. Structural formation of TPP thin films has been investigated by single crystal and powder diffractometers and Fourier transform infrared spectroscopy. The optical properties of TPP films were investigated using spectrophotometric measurements of the transmittance and reflectance at normal incidence of light. The optical constants and dispersion parameters TPP have been measured the effect of the annealing temperature and X- ray irradiation dose on the optical, electrical properties of TPP thin films as a comparative study. The electrical transport properties of TPP thin films were studied by using the two point probe technique. The electrical (DC and AC) transport properties of TPP; like resistivity, conductivity and dielectric properties dependence on temperature (297 – 473 K) and frequency (0.1 – 100 KHz) have been measured. Au / TPP / n-type Si / Al heterojunction solar cell was constructed and prepared by growing TPP film (67 nm) on n-Si wafer using thermal evaporation technique. The electrical transport mechanisms and photovoltaics properties of the solar cell have been studied.