  Li$_2$Sr[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 $-$N$-$Mn$-$N$-$Mn$-$ chains as central structural
motif. Tetragonal columns of this air and moisture sensitive nitridomanganate
were employed for electrical transport, heat capacity, and anisotropic
magnetization measurements. Both the electronic and magnetic properties are
most remarkable, in particular the linear increase of the magnetic
susceptibility with temperature that is reminiscent of underdoped cuprate and
Fe-based superconductors. Clear indications for antiferromagnetic ordering at
$T_{\rm N} = 290$ K were obtained. Metallic transport behavior is
experimentally observed in accordance with electronic band structure
calculations.
