Since the first synthesis of tribenzosubporphine in 2006, the chemistry of subporphyrins has attracted great interest. Recently, many methods have been developed to synthesize multiple-substituted subporphyrins. It is notable that the preparation of subporphyrin through the metathesis of expanded porphyrin is an effective way. Subporphyrin possesses a 14π conjugation system and C3 symmetric bowl arrangement. The properties of sub-porphyrins such as UV-Vis spectra, fluorescence and substituent effects, are much different from those of normal porphyrins, which can be well explained by four obitals model, theoretical calculations and single crystal X-ray analysis. The subporphyrins bearing large meso-aryl groups exhibited some interesting properties including higher energy transfer efficiency, enhanced fluorescence intensity and two-photon absorption. Such modified subporphyrins have great potential applications in electronics and optics.

Key words: subporphyrin, fluorescence, two-photon absorption, energy transfer, four-obital model, subchlorin