ZnO and MgxZn1-xO nanocrystals with Mg concentration of 2-30at% were grown with non-hydrolytic route employing metal cupferronate complex as precursors. ZnO nanocrystals are spherical and their sizes are independent of Zn precursor concentration, but incorporation of Mg results in MgxZn(1-x)O nanocrystal morphology and size dependence on Mg precursor concentration. MgxZn1-xO exciton emission is dominant when Mg concentration is less than 10 at%. With a further increase in Mg concentration, deep trap emission becomes dominant. MgxZn1-xO nanocrystal band gap enlarges obviously with an increase in Mg concentration from 2 to 15 at%. With a further increase in Mg concentration, MgZn1-xO band gap enlarges slowly. MgxZn1-xO band gap can be tuned from 3.30 to 3.84eV with an increase in Mg concentration from 2 to 30 at%. (c) 2007 Published by Elsevier B.V.