Yu, Craig2018-07-272018-07-272018-07-27http://hdl.handle.net/10393/37930http://dx.doi.org/10.20381/ruor-22188Organic π-conjugated molecules have garnered significant attention in the past twenty years for their potential applications in low-cost, lightweight, and flexible electronic devices. In particular, donor-acceptor (D-A) systems that involve the combination of electron-rich and electron-poor moieties in a molecule have been extensively studied due to tunability in intramolecular orbital interactions and materials properties. The theme of the current thesis is on the investigations of three different forms of D-A systems. Chapter 2 focuses on the design and synthesis of halogen-bonded organic frameworks using π-conjugated precursors as halogen bond donors and acceptors. The resulting co-crystals were subjected to single-crystal, thermal stability, and solid-state photophysical studies. In chapter 3, a series of D-A π-conjugated small molecules containing triphenylamine as the donor and an SF5 group as the acceptor was designed. The investigations include their synthesis, intramolecular orbital interactions, and photophysical properties. Chapter 4 introduces a pyrazine-containing D-A polymer using two metal-free polymerization methods, and the photophysical properties of the polymer can be significantly tuned using postpolymerization techniques.enThesis