Diamond material engineering has matured substantially during recent years and it has been described as the ultimate material for many advanced technology applications. Besides the properties of the bulk material, diamond has also unique features related to its specific point defects. Among the more than 500 defects which have been identified in diamond, the nitrogenvacancy (NV) color center has attracted a lot of interest over the last decade. The NV defect can be created in a controlled manner and can be optically addressed as a single quantum system at room temperature. It exhibits several important properties leading to farreaching applications: efficient and reliable single-photon source, spin-based quantum information processing, high resolution magnetometry based on electron spin resonance, etc. I will explain how NV centers can be efficiently formed, either in nanodiamonds or in singlecrystal bulk diamond with nanometer spatial control. I will then describe applications of NV centers to quantum information processing, as an efficient single-photon source and as part of a quantum hybrid system where an ensemble of NV centers is coupled to superconducting qubits in a stripline microwave resonator