The presented dissertation deals with the multiple functionalization of several N-heterocycles via palladium-catalyzed cross-coupling reactions. In this regard, different polyalkynylated, polyalkenylated and polyarylated pyridine, pyrazine and naphthyridine derivatives were synthesized. Moreover, photophysical and electrochemical investigations of polyalkynylated compounds were carried out. In addition, various N-phenyl diarylpyrrols were synthesized by “ligand-free” palladium-catalyzed C–H activation. A probable mechanism was proposed.