The optimization of H1 photonic crystal cavities for applications in the visible spectral range is reported, with the goal to obtain a versatile photonic platform to explore strongly and weakly coupled systems. The resonators have been realized in silicon nitride and weakly coupled to both organic (fluorophores) and inorganic (colloidal nanocrystals) nanoparticles emitting in the visible spectral range. The theoretical Purcell factor of the two dipolelike modes in the defect has been increased up to approximately 90, and the experimental quality factor was measured to be approximately 750.