Anion uptake and charge transport in a polymer of intrinsic microporosity (here PIM-EA-TB) is investigated for three cases: (i) the oxidation of ferrocene embedded into a thin film of PIM-EA-TB on a glassy carbon electrode, (ii) the reduction of protons absorbed into a thin film of PIM-EA-TB on a platinum electrode, and (iii) the potential-driven transport of anions and protons in an asymmetrically deposited free-standing PIM-EA-TB membrane working as a current rectifier or "ionic diode". In all three cases the competing effects of the diameter and hydrophobicity (size and hydration energy) of the anion are important. For free-standing membranes very high ionic diode rectification ratios (>10(3) at +/- 1 V) are observed in particular for thicker deposits of PIM-EA-TB and for chloride or perchlorate containing electrolyte. (C) 2015 Elsevier B.V. All rights reserved.