C-QuENS is an innovative research project aimed at advancing the field of quantum sensing by developing the next generation of NV-centre-based quantum sensors with quantum entanglement-enhanced performances. To achieve this goal, C-QuENS brings together six world-leading experts from four European countries who have made pioneering contributions to this research field that are essential for the realisation of the C-QuENS research vision. The project will focus on developing novel sensing protocols based on engineered correlated quantum spin states, such as entangled states and dynamical phase transitions. These protocols will outperform current quantum sensing scenarios based on independent spins in terms of sensitivity and precision. The development of these protocols will build on strong theoretical support with the development of quantum control methods, advanced signal processing protocols and experiment modelling, optimisation and analysis. C-QuENS will conduct laboratory demonstrations of these protocols using multi-qubit quantum registers undergoing magnetic dipolar interaction to create multi-qubit entanglement and many-body dynamics. In addition, the project aims to bridge the knowledge and technical gaps to implement laboratory prototypes of NV-based quantum devices that can find application in a wide range of fields as diverse as semiconductor testing or medicine. These objectives will leverage pivotal advances in diamond quantum-capable materials, including NV growth control and surface treatments. The outcomes of C-QuENS will be disseminated to the scientific community, industry, and society to promote the adoption of these technologies and maximize their impact in basic science, material manufacturing, microelectronics, healthcare, and metrology. The project will also contribute to training quantum-literate physicists and engineers and to consolidate the European supply chain on diamond quantum sensors, crucial to maintain Europe's competitiveness.