We　propose　a　series　of　azolium　poly(azolyl)borate　ionic　liquids　(ILs)　for　reversible　SO2　capture.　Density　functional　calculations　demonstrate　that　the　designed　borate　anions　can　strongly　bond　to　SO2　at　multiple　sites　with　nearly　uniform　binding　energies.　Thus,　as　well　as　high　overall　uptakes,　the　ILs　can　achieve　much　higher　effective　uptakes　(the　uptake　difference　between　absorption　and　desorption　conditions)　than　existing　SO2-capture　reagents.　The　larger　size　of　the　borate　anions,　the　evenly　distributed　negative　charge　among　the　azolyl　rings,　and　the　blocking　of　the　conjugation　by　the　tetrahedral　boron　concertedly　reduce　absorbate-absorbate　repulsion,　which　leads　to　a　large　disparity　among　binding　sites　in　other　multiple-site　SO2　sorbents.