Based on the above considerations, in this work we carried out the mechanochemical synthesis of the Cs3(Sb1-xBix)2Br9 and Cs3Sb2(I1-xBrx)9 systems (0≤x≤1) to understand the role of Sb/Bi and I/Br alloying on the structural and optical properties. For both alloying routes, we employ mechanochemistry as the main preparation technique to verify its suitability to Sbbased systems and its ability in providing phase-pure mixed compositions.