Synthesis of 3H-[1]Benzofuro[2,3-b]imidazo[4,5-f]quinolines as New Fluorescent Heterocyclic Systems for Dye-Sensitized Solar Cells

One-pot reaction of 1-alkyl-5-nitro-1H-benzimidazoles with 2-(1-benzofuran-3-yl)acetonitrile in methanol in the presence of potassium hydroxide gave 3H-[1]benzofuro[2,3-b]imidazo[4,5-f]quinolines as high-performance organic photosensitizers belonging to a new fluorescent heterocyclic system. The structure of the new compounds was assigned on the basis of their spectral and analytical data. Study of the optical properties of the title compounds revealed their interesting photophysical properties such as high fluorescence quantum yields. Their electrochemical properties were studied by cyclic voltammetry, and reversible oxidation waves were observed. The photovoltaic performance of the fluorescent heterocyclic compounds was estimated at 4.89–5.05% from the IPCE spectra and I–V curves.