We conducted experimental and computational studies, compiling datasets of compounds with established refractive indices and supplementing them with our measurements of compounds containing I⁻, Br⁻, or Br⁷⁺. We calculated the electronic polarizabilities of these ions to estimate the mean refractive index of I- and Br-containing compounds. Results were compared to the Gladstone–Dale approach, confirming their reliability in predicting optical properties.