In this project, the fabrication and characterisation of all diamond superconducting Nano-Electro-Mechanical Systems (NEMS) is proposed for the investigation of macroscopic quantum states. This involves state of the art Chemical Vapour Deposition (CVD) of diamond, doping, nanofabrication and modelling of devices. The fundamental properties of superconducting diamond, the associated mechanical properties of diamond NEMS and the characterisation of low temperature and low dimensional quantum effects will be investigated. Critically, the unprecedented resonant frequencies of diamond cantilevers allow the possibility of cooling cantilever devices down to the ground state. Coupled with its superconducting-based read out possibilities, this material offers new opportunities for challenging the Standard Quantum Limit, the study of quantum entanglement and the fabrication of superconducting diamond Qubits. This work is highly ambitious, as it aims to manipulate systems by exploiting fundamental quantum limits. However, the applicant has already demonstrated the individual constituents of this approach and thus it is not reckless to propose to integrate them.