An advanced approach with DNA-mediated bismuth tungstate (Bi2WO6) one-dimensional (1-D) nanochain assemblies for hydrogen production with 5-fold enhanced photoelectrochemical (PEC) water splitting reaction is presented. The creation of new surface states upon DNA modification mediates the electron transfer in a facile manner for a better PEC process. The UV-Vis-DRS analysis results a red shift in the optical absorption phenomenon with the interference of DNA modification on Bi2WO6, and, thus, the band gap was tuned from 3.05 eV to 2.71 eV. The applied bias photon-to-current efficiency (ABPE) was calculated and shows a maximum for the Bi2WO6@ DNA-2 (25.22 x 10(-4)%), compared to pristine Bi2WO6 (7.76 x 10-4%). Furthermore, the idea of practical utility of produced hydrogen from PEC is established for the first time with photocatalytic feedstock conversion to platform chemicals using cinnamaldehyde, 2-hydroxy-1-phenylethanone, and 2-(3-methoxyphenoxy)-1-phenylethanone in large scale by hydrogenation and/ or hydrogenolysis reactions under eco-friendly green conditions with external hydrogen pressure in an aqueous mixture. Also, the recyclability experiment delivered good yields, which further confirm the robustness of the developed catalyst.