Two-dimensional covalent organic frameworks (2D COFs) are a class of polymers that predictably organize monomers into crystalline networks with well-defined pores and high surface areas. Despite an ever-increasing number of reported COFs, these materials are typically isolated as insoluble nanocrystalline powders with poorly understood growth processes. This dissertation highlights that while there has been tremendous progress in controlling the 2D topology of COFs, there is a much weaker understanding of the factors that guide stacking of the 2D sheets (Chapter 1). We show that by truncating polyfunctional monomers, we can access hexagonal boronate ester-linked macrocycles that represent direct analogues of 2D COFs that cofacially assemble both in solution and the solid state (Chapter 2). This approach was adapted to imine-linked macrocycles and revealed that crystallization into layered structures stabilizes against rapid hydrolysis (Chapter 3). We then directly studied macrocycle self-assembly as a function of monomer identity and showed, contrary to previous reports, there is little thermodynamic gain when dimethoxy groups were added to the linker monomer (Chapter 4). This work shows that discrete macrocycles are both fascinating structures for studying self-assembly as well as excellent models for understanding the stacking interactions of 2D COFs.