Temperature dependence of the peak I1 shows a monotonous blue shift for the ligand, while a regime change around 100 K was observed for complex 5. Further, temperature dependency of the I3 peak around 2 eV (600 nm) shows a nice correlation with the temperature dependence of the HS fraction derived from magnetic measurements in SCO region 70 -180 K, confirming the existence of a synergic relation between SCO and luminescence in 5 (Fig. ).