This doctoral research focuses on the design, synthesis, and multi-modal characterization of fluorescent diamond structures containing optically active point defects, such as Nitrogen-Vacancy (NV) and Silicon-Vacancy (SiV) color centers. By combining the exceptional physical and chemical properties of the diamond lattice with the quantum characteristics of these defects, the project aims to develop high-performance platforms for advanced sensing applications, including nanoscale thermometry, magnetometry, and high-resolution imaging. To achieve this, the research utilizes precision synthesis via impurity-assisted MWCVD growth to engineer homogeneous defect distribution, followed by comprehensive characterization using confocal Raman and fluorescence microscopy, SEM or EDS analysis to ensure high quality of samples. Furthermore, additional analyses will be performed to compare the performance of different types of color centers and find an optimal combination of the diamond structure and defect type for a dedicated application.