The ternary lead bismuth magnesium borophosphate glass system (LBMBPE) with molar concentrations of (50– x) PbO– xBi 2O 3–25MgHPO 4–24B 2O 3–1Er 2O 3 ( x=10, 20, 30 and 40) was prepared using Melt quenching technique. The amorphous nature of these glass samples were confirmed with XRD studies, The spectral data from the optical absorption studies was employed to compute the spectroscopic parameters such as Racah coefficients ( E 1, E 2 and E 3), spin–orbit coupling (ξ 4 f ), configuration interaction factor ( α) and Judd–Ofelt intensity parameters ( Ω λ , λ=2, 4 and 6). The IR spectra exhibit the presence of vibrational modes of phosphates, borate radicals, bismuth, lead and magnesium ions. The Judd–Ofelt parameterization indicates the covalency and vibrationonic frequencies of the ligands with rare earth ions. The radiative parameters such as radiative transition probabilities (A), the total radiative transitional probabilities ( A T ), radiative life times ( τ R ), branching ratios ( β) and absorption cross sections (∑) were computed for certain lasing levels. The effect of compositional changes on the optical band gap is also reported. The glass systems thus developed indicate their potential lasing candidature.