To gain insight into the electronic structure of the ClMBA2SnI4 compounds, Density Functional Theory (DFT) calculations have been carried out for the R-and S-and racemic configurations. As expected, the three enantiomers show very similar electronic properties with the band gap of 2.50, 2.51 and 2.39 eV for the R-and S-and racemic configurations, respectively, which is consistent with the experimental band gap trend showing a little lower band gap for the racemic isomer compared to the chiral samples. Figure shows the projected densities of states (DOS) with the contributions of different atomic species for the R-isomers (see Figure in SI for S-and Racemic isomers). As can be seen, the band edges are dominated by I and Sn contributions, while the Cl contributions lies far from the band edges as also evidenced by the band edge wave functions (Figure ). Further, we have calculated the electronic band structure of the three systems and the results (Figure -c and Figure ) show that all the structures have a direct band gap, which is consistent with the experimental optical results.