Triazenes are very useful compounds in organic synthesis, materials science, and medicine. Among numerous reported triazene derivatives, aryl triazenes are the most investigated. Triazenes with alkynyl, vinyl, and alkyl groups were, until recently, largely underdeveloped. This thesis describes the synthesis and reactivity of the novel triazenes. Solid state luminogens are interesting for applications in light-emitting devices, fluorescent sensors, and biological probes. Because of aggregation-caused quenching, many classical fluorophores are non-emissive in the solid state. It is therefore important to develop novel luminescent compounds, which exhibit solid state (or aggregation-induced) emission. One of the most popular organic solid state emitters is tetraphenylethylene. We applied vinyl triazenes for the synthesis of tetraarylethene luminogens via C-H vinylation of aromatic compounds. In the course of this study, we found a novel class of triazoline solid state emitters, which show rare electrofluorochromic properties. The solid state luminescence of a popular palladium complex, tetrakis(triphenylphosphine)palladium(0), was overlooked in the literature. Solid state emission and redox properties of Pd(0) and Pt(0) triarylphosphine complexes were investigated in detail.