close distortions, supporting the idea that the 0D arrangement is mostly due to the type of organic cation. The more rigid PDA cations, and in particular the 1,3 ones, induce the largest distortions within the octahedra. Furthermore, as already pointed out, the distortion increases with the hardness of the halide passing from iodide to bromide and chloride. Based on these results, it is clear that, among the low-dimensional perovskites including the four ditopic cations considered in this work, the chloride samples show the highest degree of distortion which may have a relevant effect on the optical properties. In literature, broad emission is often attributed to either self-trapped excitons or emission from defect states, typically halide vacancies, while a clear connection to their structural properties is still under debate. Our experimental PL data of a broad range of materials with similar structural moieties may allow further insight into the nature of the broad emission features in 2D MHPs. DFT calculations are performed to rationalize the origin of the broad emission, distinguishing emission from self-trapped excitons (STE) and halide vacancies, VX. The energy of STE emission is calculated by the difference between the energies of the triplet and singlet states, E T1 (STE) and E S0 (STE), respectively, calculated at the equilibrium geometry of the STE, see schematic representation in Figure :