SUMO aims to set the basis of a new architecture for quantum computation and simulation, in which information is encoded in molecular spin qubits that are read-out and communicate by coupling to a superconducting resonator. This technology has a high scalability potential based on the microscopic and reproducible nature of the molecules and on the possibilities they offer for embodying multiple qubits, which provide an extra dimension to increase computational resources and to implement noise-resilient logical qubits. The proposal focuses on two specific targets, which are crucial milestones for the realization of such magnetic quantum processor. The first is the implementation of active quantum error correction in magnetic molecules. The second is the attainment of strong coupling between individual molecular spins and single microwave photons It has a strong multidisciplinary character and benefits from the European leadership in molecular magnetism.