Sulfur‐doped Eosin‐B (SDE‐B) photocatalysts were synthesized for the first time utilizing sublimed sulfur (S8) as a dopant in an in situ thermal copolymerization technique. Sulfur doping not only increased Eosin‐B (E‐B) absorption range for solar radiation but also improved fixation and oxygenation capabilities. The doped sulfur bridges the S‐S bond by substituting for the edge bromine of the E‐B bond. The improved photocatalytic activity of SDE‐B in the fixation and oxygenation of NAD+/NADP+ and sulfides using solar light is attributed to the photo‐induced hole of SDE‐B's high fixation and oxygenation capacity, as well as an efficient suppression of electron and hole recombination. The powerful light‐harvesting bridge system created using SDE‐B as a photocatalyst works extremely well, resulting in high NADH/NADPH regeneration (79.58/76.36%) and good sulfoxide yields (98.9%) under solar light. This study focuses on the creation and implementation of a sulfur‐doped photocatalyst for direct fine chemical regeneration and organic transformation.