For some selected samples of the DA2Ge(Br1-xIx)4 system, namely for x = 0, 0.25, 0.5, 0.75, and 1, we also carried out low temperature PL measurements at 77 K. These are reported in Figures , respectively. For all the samples the low-temperature PL measurements show intense emission and a different structuring of the bands for the diverse specimens. For DA2GeBr4 (Fig. ), a very broad and continuous emission is observed from about 600 to about 800 nm. For the iodide containing samples, a narrowing of the PL with respect to RT data is observed, with an emission peaking in the range 630-690 nm and extending over a broad region (550-850 nm). A table summarizing the results of the LT PL measurements is reported in the SI (Table ). Moreover, at low temperature, lifetimes become significantly longer, by the order of μs, with mixed compositions showing higher values with respect to the two end-members.