Coupling clean energy generation and environmental remediation using novel material designs and technologies is very promising. Herein, we propose the design of heterojunction photocatalysts using porous metal-organic frameworks (MOFs) and a semiconductor support for simultaneous H2 generation as well as organic pollutants degradation in wastewater. For the concept validation, hierarchical structures containing leaf like Co and Zn-ZIF-L nanoplates decorated on BaTi2O5 (BT2) nanofibers (NFs) were fabricated and investigated. A significant improvement in the photoelectrochemical (PEC) water splitting was observed owing to the synergistic effects resulting from the preferred band energies alignment of BT2 and Co-ZIF-L. The efficient electron-hole pair separation and high solar energy harvesting were achieved. Methylene blue as a model pollutant was employed to elucidate the effect of pollutant degradation efficiency on H2 production. The Co-ZIF-L@BT2 exhibited high photocurrent density with 0.33 mA cm-2 at 1 V versus Ag/AgCl. Meanwhile, 76 % of methylene blue is degraded in 120 min from wastewater. The present work evaluates the synergistic effect of well-integrated composite photocatalysts toward the performance enhancement in simultaneous pollutant degradation and H2 production. Also, it provides deep insight into the pollutant role towards boosting H2 production.