We report the structural, lattice dynamics and electronic structure of mixed halo-fluoride scintillators MClF (M = Ca, Sr) based on density functional theory within generalized gradient approximation. The pressure dependent structural parameters and zone centered phonon frequencies are in reasonable agreement with the available experimental data. Both the structures are dynamically stable up to 50 GPa. MClF compounds are found to have a direct band gap along Γ-Γ direction at ambient as well as under pressure. It is found that these materials can serve as good storage phosphors in the low pressure region from the calculated electronic structure and optical spectra. © 2015 AIP Publishing LLC.