Organic molecules featuring extended π-conjugated systems have emerged in the last decade as promising materials for organic based devices. Among these π-conjugated molecules, ladder-type systems (materials with flat and rigid skeletons) are one of the most interesting candidates because the annelation eliminates conformational disorders, leading to attractive photophysical and electronic properties, such as intense luminescence and high carrier mobility. To further improve the photophysical properties of these materials several main group elements have been incorporated into these ladder-type structures. These elements impart interesting features such as more effective orbital interactions, diversity in coordination numbers, and intriguing structural motifs that can be used to tune properties. Boron is an attractive main group element that has been used to prepare fascinating π-conjugated materials with potential application in optoelectronics. Arguably the most important characteristic of a three-coordinate boron center is the empty p-orbital, which allows effective conjugation of organic π-systems with and through boron. Furthermore, the exchange of carbon for the more electropositive boron can also alter the electronic characteristics of a compound significantly. This thesis focused on the design and development of new boron-containing heterocycles and their photophysical and electronic properties. Interestingly, these remarkable boroncontaining polycyclic aromatic hydrocarbons can act as strong electron acceptors and it was possible to isolate and characterize their mono- and di-reduced species. Furthermore, the reactivity of these molecules towards small molecules such as carbon monoxide and carbon dioxide was also investigated.