Communication: Thin films of zirconia and zirconates have a variety of important applications. MOCVD is an attractive technique for the preparation of these films, but there are a number of drawbacks associated with the currently used Zr precursors. This paper reports on a new class of precursor of the form [Zr(OR)(2)(thd)(2)], where R = Pr-i or Bu-t, which allows growth by liquid injection of ZrO2 under transport-controlled conditions at significantly lower temperatures than can be achieved with conventional sources.