Chemical Symmetry Breaking Enables Interconversion between Altermagnetic and Compensated Ferrimagnetic States

Altermagnetism and fully compensated ferrimagnetism are distinct classes of zero-net-magnetization order that combine antiferromagnetic compensation with ferromagneticlike spin splitting. In altermagnets, spin splitting arises from crystal symmetry and alternates in momentum space, whereas in compensated ferrimagnets it originates from band-filling constraints and remains uniform across the Brillouin zone. A controllable pathway connecting these regimes has remained elusive. Here we show that chemical symmetry breaking provides a general mechanism to interconvert these two orders. Using symmetry analysis, tight-binding theory, and first-principles calculations, we identify the Cairo-pentagonal lattice as a platform that generically hosts altermagnetic order and demonstrate its conversion to a fully compensated ferrimagnetic state via site-selective functionalization that lifts sublattice symmetry without inducing net magnetization. This transition removes symmetry-enforced momentum-space sign reversal of spin splitting, leading to enhanced anomalous Hall response and the emergence of magneto-optical Kerr effects. Our results establish a material route for interconverting zero-magnetization orders and identify chemically programmable two-dimensional metal-organic frameworks as a versatile platform for symmetry-controlled spintronic functionalities.