AGN Host Galaxies in COSMOS-Web: Linking Structural Evolution and Star Formation Quenching up to $z=5$

The role of active galactic nuclei (AGNs) in the suppression of star formation and structural evolution of galaxies during their transition from star-forming to quiescent systems remains unclear. We analyze 3,955 AGNs selected through five multiwavelength diagnostics at 01010.5) generally exhibit sizes comparable to those of SFGs despite suppressed star formation. Toward lower redshifts, they increasingly approach the QG size-mass relation, accompanied by declining specific star formation rates (sSFRs) and increasing Sérsic indices. In contrast, lower-mass AGN hosts remain close to the SFG relation across the redshift range. Overall, AGN hosts exhibit relatively mild size evolution, following Rₑ∝(1+z)-0.6 over $02.2$, however, some AGN hosts exhibit suppressed star formation while retaining relatively extended structures. These findings suggest that some AGN hosts may follow alternative evolutionary pathways in which star formation suppression precedes substantial structural compaction.