xx, 318 p. ： ill. (some col.) / Highly conjugated, carbon rich molecules are of great interest due to their unique optoelectronic properties. These molecules are now recognized as suitable materials for advanced materials applications such as light-emitting diodes, photovoltaics, and thin film transistors. Of particular interest is the indenofluorene (IF) scaffold, a 6-5-6-5-6-fused ring system that holds a striking topological similarity to pentacene, a very successful electron donating organic semiconductor. Also of interest is another class of compounds referred to as tetrakis(arylethynyl)benzenes, TAEBs, which are cruciform-shaped molecules that possess numerous pathways for electronic and photonic transfer and are amenable to a host of substitution patterns. Chapter I examines the history of the IF scaffold and its development over the last century through the use of literature examples relating to both its synthesis and potential use as an emerging class of electron accepting materials. Chapter II introduces the feasibility of stable, fully conjugated IFs. Two examples of 5,6,11,12-tetraethynyl-indeno[1,2- b ]fluorenes are synthesized where their structural and optoelectronic properties are explored. Chapter III further explores the IF scaffold and outlines the synthesis of a series of 6,12-diethynylindeno[1,2-b ]fluorenes in conjunction with detailed computational, structural, and photophysical studies. Chapter IV discusses the synthesis and characterization of a series of 6,12-diarylindeno[1,2- b ]fluorenes and examines their structural and optoelectronic properties. Chapter V describes a series of donor/acceptor-functionalized TAEBs that incorporate the 4,4-difluoro-4-bora-3a,4a,-diaza-s -indacene moiety, better known as BODIPY, as the acceptor unit. Additionally, two TAEB molecules and three structurally related bis(arylethynyl)benzene (BAEB) isomers where only acceptors are used to evaluate the effectiveness of the donor group are synthesized. This dissertation includes both previously published and unpublished co-authored material. / Committee in charge: Professor David R. Tyler， Chairperson； Professor Michael M. Haley， Advisor； Professor Victoria J. DeRose， Member； Professor Shih-Yuan Liu， Member； Professor Scott D. Bridgham， Outside Member