This talk will describe our efforts to control the structure of synthetic polymers from single-chains to networks. Motivated by nature, polymer chemists have long sought methods and strategies for the synthesis of polymers with precise structure. Existing methods for precision polymer synthesis typically require a trade-off between structural control and atom economy/scalability. Seeking more efficient strategies, we have developed an iterative exponential growth plus sidechain functionalization (IEG+) approach that enables reasonably efficient gram-scale syntheses of macromolecules with absolute control over mass, sequence, and stereochemistry. The first part of this talk will focus on the synthesis and initial applications of IEG+ polymers. The second part of this talk will describe our interests in using the tools of physical organic chemistry to study and control the structure of covalent polymer networks. These studies have allowed us to address longstanding questions in the theory of non-entangled elastic networks. Building from these insights, we have developed a new class of polymer metal-organic-cage materials – polyMOCs – that feature interesting mechanical behaviors.