Octahedral gold nanocrystals have been fabricated in an alcohol ionic liquid by a one-step method in the absence of any extra capping agent. The method is based on a reaction of HAuCl4 center dot 4H(2)O in 1-(3-hydroxylpropyl)-3-methylimidazolium tetrafluoroborate (C(3)OHmimBF(4)) by microwave heating. Upon adjusting HAuCl4 center dot 4H(2)O concentration and reaction temperature, nanoplates and micrometer-sized particles have also been obtained.