Polycyclic aromatic hydrocarbons (PAHs) have been enjoying a renewed interest due to their potential application in organic based optical and electronic devices that are expected to be key components in the next generation of lightweight, flexible and inexpensive molecular electronics. Therefore, the objective of this research work is the development of sulfur and selenium rich heterocycles on large π-aggregated molecules.

　Aromatic cyclic polysulfides are also well-known, reputed and popular hetrocycles to sulfur chemists due to the promising application to material science and cytology. Naphthalene sulfonamide was tried to convert into naphthalene dithiol but surprisingly a novel method for the synthesis of dinaphtho[1,2-b ;2' ,1' -d ]chalcogenophenes was found. Synthesis, mechanism, photo physical and solid-state properties of chalcohenophenes are studied.

　Pentathiepins are developed on benzene or other simple hetrocycles up to now, and therefore cyclic polysulfides are synthesized on polyaromatics such as naphthalene, phenanthrene and pyrene. Solid-state properties of these compounds are studied in compare with benzopentathiepin.

　Benzopentathiepin was also tried to modify by insertion of one or two selenium atoms. These ring were found very labile in benzene. Polyaromatics can stabilize such rings by acting as thermodynamic stabilization unit. Furthermore, using of different substituents also kinetically stabilized cyclic polychacogeneides.

　Finally,　phenanthropolychalcogenides were synthesized. A novel selenium extrusion reaction from　tetrathia- selenepin ring was observed by ¹H NMR in ambient light. The details of these reactions, synthesis, mechanism and properties are described.
All interestining above topics are studied throughout the research period.