Polymers of intrinsic microporosity (PIMs) are recently developed, prominent, ladder-type, soluble, and permanently porous polymers with Brunauer–Emmett–Teller (BET) surface areas of 760-850 m²/g. Owing to the deficient chain orientation from a twisted core structure, it inherits a combined benefit of a large surface area porous material and the versatility of a linear polymer. We have produced amidoxime, ketone, imine and hydrazone derivatives of PIM-1 for applications in gas capture and storage, water treatment, uranium capture, and biomedicine. In doing so, we also introduced noninvasive functionalization of PIMs with volatile reagents, particularly for amidoxime, resulting in an increase in carbon dioxide capacity by 17% and surface area by 20% without affecting its film-forming ability. The introduction of amidoxime was achieved through a rapid reaction of nitrile groups of PIM-1 with hydroxyl amine under reflux conditions and confirmed through common analytical techniques. Additionally, we have successfully transformed PIM-1 nitriles into four new functional groups – ketones, alcohols, imines, and hydrazones – in a single step using a non-solvent approach that preserves surface area. These modifications are simple, scalable, and reproducible, and offer unique new directions for chemical modification of porous materials.