Abstract: Polar molecules offer long-range anisotropic interactions, which are fundamental to a wide variety of phenomena, from ferrofluid behavior to the folding of proteins. Recent demonstrations of cooling and trapping polar molecules have made it possible to study these particles in the quantum regime, making them highly attractive for applications such as quantum information storage and exploring novel condensed matter phases. In this talk, I will report on the quantum control of dipolar fermionic NaK molecules, which we have synthesized in the ground state at ultracold temperatures as low as 300 nK. Using microwaves, we have coherently manipulated not only the rotational states of the molecules, but also the nuclear spin degree of freedom. I will present our observation of nuclear spin coherence times on the scale of 1 second, and discuss its implications for quantum memory and probing new physics via Hertz-level precision spectroscopy.