We describe the integration of polar molecules with mesoscopic solid state devices in a way that produces robust, coherent, quantum‐level control with applications for quantum information processing. The exceptional features of polar molecules, i.e. long‐lived rotational states in combination with electric dipole moments of several Debye, provide the necessary ingredients to achieve strong coupling to the quantized field of a high‐Q microwave cavity. We discuss two scenarios, where quantum information is stored either in rotational states of a single molecule or in collective spin excitation of an ensemble of molecules. In the latter case we benefit from an enhanced coupling strength, which allows a coherent transfer of quantum information between molecules and solid state qubits.