Furthermore, we have also shown that simple alkyl substitution around the anion binding site renders the receptors remarkably watertolerant and grants them outstanding anion transport properties. For example, the affinity of 2 toward iodide exceeds 10 4 M -1 even in the presence of 10% water in THF, while its activity in Cl -/NO3 -exchange across lipid bilayers surpasses the activity of previously described CH-bonding transporters. Resorcin [4]arene 2 shows also remarkable Cl -> OH -selectivity in transport experiments, likely due to the soft nature of its CH donors and their resistance towards deprotonation. Such selectivity is highly desirable in medicinal applications because it is believed to minimize the toxicity of transporters.