The present invention relates to nanocrystals consisting of a homogeneous ternary or quaternary alloy having the composition M1.sub.1-xM2.sub.xA and M1.sub.1-xM2.sub.xA.sub.yB.sub.1-y, respectively, a process for its production, as well as to uses of such nanocrystals such as as short wavelength light-emitting devices, and in the detection of analytes, in particular biomolecules.