Novel Sr2ZnMoO6:Mn4+ deep red-emitting phosphor is synthesized by solid-state reaction method. Emission band peaking at ∼705 nm is observed within the range 650–790 nm. The influences of the crystal field and the “Mn4+-ligand” bonding are analyzed. The luminous mechanism is explained by Tanabe-Sugano energy level diagram of Mn4+.