The emission lines of bound and free excitons and their phonon replicas were observed in the luminescence spectra of ZnP₂-D₄ ⁸ crystals doped with Mn, Sn, Cd and Sb measured at 10 K. The emission lines are described by the model of axial center levels. Models of the bands of the bound excitons with different axial centers (Mn, Sn, Cd and Sb) are presented. It was observed that the indirect transitions in the excitonic bands were nonpolarized and that the direct transitions were polarized. The minimal direct energy gaps in the polarization Eâ̂¥c are due to the allowed ₁→₁ transitions, and the gaps in the polarization E⊥c are due to the ₂→ ₁ transitions. The temperature shift coefficient of the bands gaps differs for different polarizations in the temperature interval from 2 to 10 K (ΔE/ΔT=3.5 meV/K and 1 meV/K for Eâ̂¥c and E⊥c, respectively). The optical constants n, k, ε₁, ε_2, d²ε₁/dE ² and d²ε₂/dE² were calculated for the energy interval 1.5-10 eV using the Kramers-Kronig analysis of measured reflection spectra. The features observed in these spectra were interpreted using two types theoretical calculations of band structure as optical transitions.