In this work, we have employed this triradical as a representative system to benchmark and standardize the computational methodology. At first, doublet-quartet energy gaps of this triradical are computed employing DFT based BS-DFT and CBS-DFT methods. As discussed before, in the case of three localized spins in three centers, low energy spectra For multi-reference calculations, it is well-known that proper choice of active space and the number of roots included in state-averaging are crucial for the prediction of appropriate results. This is also been experienced in our previous work and has also been reported by Llanos et al. in the study of inorganic systems. For the description of triradicals, the minimal active space required for qualitative description involves three unpaired electrons distributed in the three active orbitals i.e., CAS (3,3). This active space leads to 7 orbital configurations giving rise to 1 quartet and 8 doublet configuration state functions (CSFs).