Developing efficient and affordable trifunctional electrocatalysts for the oxygen evolution reaction (OER), oxygen reduction reaction (ORR), and hydrogen evolution reaction (HER) is critical for advancing hydrogen-based clean energy technologies. In this work, we report a porphyrin-pyrene-based conjugated porous polymer incorporating Fe and Co (FeCoPP), grafted onto electrophoretically exfoliated graphene (FeCoPP/G). The material is intercalated between graphene layers, enhancing charge density at the active sites and facilitating reversible oxygen electrocatalysis, with a ΔE of 0.615 V. The integrated water-splitting system achieves 10 mA cm⁻² at 1.61 V, highlighting excellent trifunctional activity. Mechanistic insights from DFT, in-situ Raman, and FT-IR spectroscopy reveal strong interactions between the active sites and intermediates, supported by reduced d-orbital occupancy upon adsorption, enabling effective charge transfer. The FeCoPP/G cathode powers high-performance rechargeable Zn-air batteries, achieving peak power densities of 237 mW cm⁻² (liquid) and 161 mW cm⁻² (solid), along with high specific energy and prolonged cycling stability. Moreover, the self-assembled Zn-air battery successfully drives overall water splitting, demonstrating the multifunctionality and promise of FeCoPP/G as a sustainable electrocatalyst for energy conversion and storage.