The synthesis of a series of functional artifical ion channels is described. Candidate structures are assembled from a modular construction set of subunits consisting of a core crown ether unit for structural organization, multiple macrocyclic tetraester wall units to span a bilayer membrane, and polar head units to impart amphiphilic character. The modular assembly approach allowed the efficient synthesis of a suite of compounds but the inherent properties of the construction set limited the range of synthetically accessible structures. 1. Introduction 2. Design 3. Making the Wall Components 4. Joining the Pieces 5. Transporter Activity 6. What Next?