The creation of a combined radiative state at 2.95–3.1 eV in the phosphor ${CaSO}_4-{Dy}_{ }^{3+}$ has been investigated using vacuum ultraviolet and thermoactivation spectroscopy methods. It is shown that the combined radiative electronic state is formed from the radiative electronic states of the impurity electronic trapping centers ${Dy}_{ }^{2+}-{ SO}_4^{-}$ and the intrinsic electronic radiative states ${SO}_4^{3-}-{SO}_4^{-}$ during the excitation of the anion complex ${SO}_4^{2-}$, as a result of charge transfer from the excited anion complex $O_{ }^{2-}-{Dy}_{ }^{3+}$ to the impurities and the neighboring anion complex $O^{2-}-{ SO}_4^{2-}$. In the ${CaSO}_4-Dy$ phosphor, the combined radiative electronic state and impurity emission of ${Dy}_{ }^{3+}$, 2.16 eV and 2.56 eV are excited by photons with energies of 3.95–4.0 eV and 4.5–4.6 eV. Energy transfer from the matrix to the ${Dy}_{ }^{3+}$ impurities is revealed upon thermal exposure as a result of the ionization of the electronic capture centers of ${Dy}^{2+}$ and ${SO}_4^{3-}$.