Stable organic radicals have gained attention due to their wide applications in organic molecular magnetism (OMMs), molecular spintronics, etc. Several stable radicals like nitronyl nitroxide, imino nitroxide, verdazyl, oxoverdazyl, etc have been synthesized extensively. One of the super stable radicals is the 1,2,4-benzotriazinyl radical popularly known as Blatter’s radical. Our research focuses on the modeling of diradicals with high-spin ground state and strong ferromagnetic exchange interactions based on the stable known radicals. We use a range of high level computational methods to characterize the magnetic exchange interactions in the diradicals including broken-symmetry density functional theory (BS-DFT), constraint broken-symmetry density functional theory (CBS-DFT), complete active space self-consistent field (CASSCF), N-electron valence state perturbation theory (NEVPT2), etc.