ABSTRACT: Advancing iontronics with precisely controlled ion transport is fundamentallyimportant to bridge external organic electronics with the biosystem. This long-standing goal,however, is thus far limited by the trade-off between the active ion electromigration and idlediffusion leakage in the (semi)crystalline film. Here, we presented a mixed-orientationstrategy by blending a conjugated polymer, allowing for simultaneously high ionelectromigration efficiency and low leakage. Our studies revealed that edge-on aggregationwith a significant percolative pathway exhibits much higher ion permeability than that of theface-on counterpart but encounters pronounced leakage diffusion. Through carefullyengineering the mixed orientations, the polymer composite demonstrated an ideal switchableion-transport behavior, achieving a remarkably high electromigration efficiency exceeding onequadrillion ions per milliliter per minute and negligible idle leakage. This proof of concept,validated by drug release in a skin-conformable organic electronic ion pump (OEIP), offers arational approach for the development of multifunctional iontronic devices.