Plasmonic nanocrystals were attracting a lot of attention both for fundamental studies and different applications, from sensing to imaging and optoelectronic devices. Transparent conductive oxides represent an interesting class of plasmonic materials in addn. to metals and vacancy-doped semiconductor quantum dots. A rational synthetic strategy of high-quality colloidal Al-doped Zn oxide nanocrystals is reported. The presence of substitutional Al in the Zn oxide lattice accompanied by the generation of free electrons is proved by tunable surface plasmon absorption in the IR region both in soln. and in thin films.