Unraveling the Mystery: What is NADPH in Photosynthesis? Learn how this tiny molecule plays a crucial role in the process of photosynthesis and how it helps plants produce essential organic compounds. Nicotinamide Adenine Dinucleotide Phosphate Hydrogen (NADPH) The full form of NADPH is nicotinamide adenine dinucleotide phosphate hydrogen. It plays a crucial role in many of the chemical reactions that make up the procedure of the photosynthesis. NADPH is a product of the first level of photosynthesis. NADP + Definition. NADP + is a coenzyme that functions as a universal electron carrier, accepting electrons and hydrogen atoms to form NADPH, or nicotinamide adenine dinucleotide phosphate. NADP + is created in anabolic reactions, or reaction that build large molecules from small molecules. NADPH donates the hydrogen (H) and associated Jlmzj.