Self-assembling porphyrins are promising materials to mimic natural bacteriochlorophylls c, d, or e encountered in the chlorosomes of photosynthetic bacteria. We have studied four novel magnesium porphyrins mimicking this chlorosomal antenna system. In contrast to previous articles reporting synthetic Zn-porphyrins, our studies focus on porphyrins with Mg as the central atom, which mimic more closely the natural bacteriochlorophylls. The analysis of time-resolved photoluminescence dynamics based on the decay-associated emission spectra shows a short-lived component associated with the supramolecular architecture. It confirms the ordered nature of the investigated porphyrins and suggests that these self-assemblies can be used as artificial antennae in light-harvesting devices like biomimetic solar cells.