The advances in materials science increasingly demand novel functionalized materials. Porphyrins fused with aromatic moieties represent attractive largely π-extended structures, offering new opportunities in molecular and organic electronics.1-4 In this presentation, new synthetic methods to fuse different type of aromatic rings to the porphyrin periphery will be presented. These new methods have led to the synthesis of novel large π-extended molecular structures incorporating both porphyrins and other aromatic components including acenaphtho[1,2-b]pentacene-, acenaphtho[1,2-b]pentacene quinone, benzodithiophenes and cyclooctatetraenes. Unprecedented electronic and photophysical properties have discovered for these π-extended porphyrins. For example, an unusual trend was observed in the florescence quantum yield upon converting thiophene-attached benzoporphyrin to naphthodithiophene-fused porphyrin. A remarkable light effect was obtained with a acenaphtho[1,2-b]pentacene-fused porphyrin-phthalocyanine heterojunction device, which exhibited high ammonia sensitivity. The characterizations of these π-extended porphyrins including time-resolved emission and transient absorption spectroscopy, cyclic voltammetry, DFT calculations will also be presented. Reference Stepien, E. Gonka, M. Zyla and N. Sprutta, Chem. Rev., 2017, 117, 3479-3716.Narita, X. Y. Wang, X. Feng and K. Mullen, Chem. Soc. Rev., 2015, 44, 6616-6643.P. Lewtak and D. T. Gryko, Chem. Commun., 2012, 48, 10069-10086.K. S. Davis, A. L. Thompson and H. L. Anderson, J. Am. Chem. Soc., 2011, 133, 30-3.Hu, M. B. Thomas, W. A. Webre, A. Moss, R. G. W. Jinadasa, V. N. Nesterov, F. D’Souza and H. Wang, Angew. Chem. Int. Ed., 2020, 45 (132), 20250-20257.Moss, Y. Jang, J. Arvidson, V. N. Nesterov, F. D’Souza and H. Wang, Chem. Sci., 2022, 13, 9880 -9890.Moss, D. E. Nevonen, Y. Hu, V. N. Nesterov, V. Nemykin and H. Wang*, ACS Phys. Chem. Au, 2022, 2, 6, 468-481.Washburn, R. Kaswan, S. Shaikh, A. Moss, F. D’Souza and Hong Wang, J. Phys. Chem. A., 2023,127 (43):9040-9051.Cooper, A. Alsaleh, S. Kumar, W. Rackers, V. N. Nesterov, F. D’Souza, S. A. Vinogradov and H. Wang, Chem. Eur. J., 2023, e202302013.Moss, Y. Jang, H. Wang, F. D’Souza, ChemSusChem, 2023, 16 (8), e202202289.