In this research, a green alga (Paulschulziapseudovolvox sp.) based biological photovoltaic cell (BPV) was designed. This clean energy-friendly BPV produced photocurrent as a result of illuminating the photoanode and cathode electrodes immersed in the aqueous medium with solar energy. For this purpose, both electrodes were first coated with conductive polymers with aniline functional groups on gold electrodes. In the cell, the photoanode was first coated with a gold-modified poly 4-(2,5-di(thiophen-2-yl)-1H-pyrrol-1-yl)benzamine polymer, (P(SNS-NH2)). Cytochrome C (Cyt. C) material was used to provide crosslink formation with bis-aniline covalent bonds with the conductive polymer using electrochemical techniques. Paulschulziapseudovolvox sp., one of the green algae that can convert light energy into chemical energy, is attached to this layered electrode surface. The cathode of the cell is attached to the gold electrode surface with poly 4-(4HDithieno[3,2-b : 2′,3′-d]pyrrole-4-yl)aniline (P(DTP-Aryl-Amine)). Then, the bilirubin oxidase enzyme was immobilized on this film surface with glutaraldehyde activation. This cell, which can use light thanks to green algae, oxidizes and splits water, and oxygen is obtained at the photoanode electrode. At the cathode electrode, the oxygen gas is reduced to water by the bio-electro-catalytic method. To obtain high photocurrent from the BPV, necessary electrochemical and chemical optimizations were made during the design of the system to increase the amount of electrons that were transferred and fasten its transfer rate. While the photocurrent value generated by the designed BPV in optimum conditions and in the pseudo-steady state is 10 mA/m2, the maximum power value obtained is 46.5 mW/m2. In addition to the production of the green algae-based BPV generating highly efficient electricity which is the main of target of this study, some studies have also been carried out to show whether this system can be used as a pesticide biosensor. Atrazine and diuron biosensing via the BPV system was analytically characterized and recovery and interference studies related to pesticide biosensor property of the BPV were also investigated.