Perylene derivatives are novel chromophores with great potential in organic optoelectronics. Yet, the synthetic entry into this class of molecules is hitherto quite limited. This doctoral thesis described the synthesis and characterization of functionalized perylene derivatives and their functionalization. In the first part of the thesis, synthesis of ortho-bay functionalized perylene (1,2,7,8-tetrasubstituted) derivatives via a double Wittig-Knoevenagel benzannulation protocol is described. Preliminary photophysical and electrochemical studies indicate that the frontier orbital energy levels of these new perylene systems are modulated by electronic, regiochemical, and conformational effects. Preliminary OFET studies indicate that few of the synthesized ortho-bay functionalized (Z-shape) perylene derivatives with low LUMO energies are promising candidates for n-channel semiconductors. In the second part of the thesis, regioselective stepwise cyanation on Z-shape perylene diimide on the molecular long axis (3,4,9- peri positions) and the short axis (1,7- bay positions) is described. The nirile functional groups preferentially tune the frontier orbitals by lowering the LUMO of Z-shape perylene diimide (PDI). Pentacyanated Z-shape PDI showed a positive reduction potential of 0.12 eV and the lowest LUMO energy of -4.92 eV. In the third part of the thesis, selective synthesis of ortho and bay functionalized perylene derivatives via a Wittig-Knoevenagel benzannulation strategy is described. Since the reactive peri sites are unsubstituted in these functionalizaed perylenes, a wide range of further functionalization can be carried out, including the synthesis of push-pull perylenes, and higher rylenes. A novel kind of biscylised perylene chromophore containing fluorene units in its structure is developed. It exhibit good solubility and high fluorescence quantum yield. Because of high fluorescence quantum yields in solid state, biscyclised perylene is a promising candidate in OLED application.