Abstract Nanocrystalline (CuInS2)0.5(ZnS)0.5 is prepared by hot injecting stoichiometric amounts of a solution of Cu(acac)2, In(acac)3, and Zn(acac)2 in oleylamine and an oleylamine solution of S into a preheated reaction vessel also containing oleylamine (250 °C, 15 min).