Perhaps the most blatant display of utilizing an alien race for his own ends occured[sic] when Palpatine ordered Count Dook u to take the plan for the Geonosian-designed super weapon the Death Star into his hands supposedly for safe keeping.
A technologically advanced race (Dooku's solar sailer was a gift from the Geonosian Archduke, Poggle the Lesser), the Geonosians were vital to the plot to resurrect the fallen Kaleesh warrior Qymaen jai Sheelal, as the fearsome cyborg General Grievous.
The techniqes used to rebuild Grievous would later be employed to rebuild the shattered form of Darth Vader, forever encasing him in life-saving armor. Vader would, of course, emerge as a vital player in the galactic conflict to come.