Li2Sr[MnN]2 : A magnetically ordered metallic nitride

${\mathrm{Li}}_{2}\mathrm{Sr}{[\mathrm{MnN}]}_{2}$ single crystals were successfully grown out of Li-rich flux. The crystal structure was determined by single-crystal x-ray diffraction and revealed almost linear $\ensuremath{-}\mathrm{N}\ensuremath{-}\mathrm{Mn}\ensuremath{-}\mathrm{N}\ensuremath{-}\mathrm{Mn}\ensuremath{-}$ chains as central structural motif. Tetragonal blocks air moisture-sensitive nitridomanganate employed for electrical transport, heat capacity, anisotropic magnetization measurements. Both the electronic magnetic properties are most remarkable, in particular increase susceptibility with temperature that is reminiscent underdoped cuprate Fe-based superconductors. Clear indications antiferromagnetic ordering at ${T}_{N}=290$ K obtained. Metallic transport behavior experimentally observed accordance band calculations.