π‐Contraction Induces High‑Spin Co Centers in 2D Conductive MOFs for Efficient Oxygen Reduction

ABSTRACT Two‐dimensional conductive metal–organic frameworks (c‐MOFs) are promising electrocatalysts for the oxygen reduction reaction (ORR), yet nearly all optimization strategies have focused on metal‐node modification while the ligand scaffold remains largely unexplored. Here, we report an unconventional “π‐contraction” strategy that excises the peripheral benzene rings from metallophthalocyanine (MPc) to afford contracted metalloporphyrazine (MPz) ligands (M = Co, Ni). Trimming decreases π‐electron density on the carbon framework and directs charge to the metal center, thereby reshaping its electronic structure. In CoPz–MOF, this contraction uniquely induces a high‐spin Co 3d station and stabilizes mixed Co(I)/Co(II) valence states—features absent in CoPc MOF and Ni‐based analogues. DFT calculations confirm that the high‐spin configuration confers the strongest oxygen adsorption affinity among the series, while the presence of Co(I) species further promotes O 2 chemisorption during the onset stage of ORR. Electrochemically, CoPz–MOF delivers a half‐wave potential of 0.84 V with a preferential four‐electron pathway, outperforming its counterparts. In zinc–air batteries, it achieves a peak power density of 125.6 mW cm −2 and stable operation over 500 h. This work establishes ligand‐level conjugation engineering—rather than node‐metal substitution—as a powerful strategy for tailoring metal‐center electronic structures in c‐MOF electrocatalysts.