In order to fabricate the semiconductor-based photodetectors, Ni and Zn-centered nicotinate complexes were synthesized chemically. The synthesized Ni and Zn-centered nicotinates were analyzed using Ultraviolet–Visible (UV–Vis) spectrometry and thermogravimetric analysis (TGA) techniques. The synthesized complex materials were coated between Al and p-Si by spin coating technique, and Al/Ni-centered nicotinate/p-Si and Al/Zn-centered nicotinate /p-Si sandwich structures were obtained. The photoelectrical characteristics of the produced devices were analyzed by photo-transient (I-t) and current–voltage (I–V) measurements under dark and different luminous power intensities. In light of the measurements made, series resistance, ideality factor, and barrier height values, which are very important electrical parameters, were obtained and evaluated in particular using different techniques. Various parameters such as specific detectivity, responsivity, and photosensitivity were calculated using I-t analysis based on exposed light power. In addition, external quantum efficiency (EQE) values were calculated with I-t measurements carried out under lighting conditions at different wavelengths. Last of all, the Al/Ni-centered nicotinate/p-Si and Al/Zn-centered nicotinate/p-Si structures have good performance in photodetector and photodiode designs and can be developed for use in optoelectronic technologies.