We report the synthesis, structure, and physical properties of a new quaternary nitride ${\mathrm{LaCr}}_2{\mathrm{Ge}}_2\mathrm{N}$. The compound crystallizes in the ${\mathrm{CeCr}}_2{\mathrm{Si}}_2\mathrm{C}$-type structure ($P4$/mmm), featuring distinctive ${\mathrm{Cr}}_2\mathrm{N}$ square sheets within ${\mathrm{Cr}}_2{\mathrm{Ge}}_2\mathrm{N}$ block layers. Physical characterizations reveal enhanced electron correlations evidenced by a Sommerfeld coefficient substantially larger than band calculations and pressure-induced deviation from Fermi-liquid behavior. Magnetic measurements show short-range antiferromagnetic correlations developing around 460 K, followed by long-range magnetic ordering at 14 K. Additionally, subtle anomalies at 378 K suggest possible electronic ordering. First-principles calculations reveal nearly flat Cr-$3d$ bands near the Fermi level and predict a striped antiferromagnetic ground state. This work demonstrates how electron count variation in the ${\mathrm{CeCr}}_2{\mathrm{Si}}_2\mathrm{C}$-type structure family leads to magnetic ordering in ${\mathrm{LaCr}}_2{\mathrm{Ge}}_2\mathrm{N}$, contrasting with the paramagnetic behavior of ${\mathrm{LnCr}}_2{\mathrm{Si}}_2\mathrm{C}$ compounds.

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• Antiferromagnetism
• Charge density waves
• Electrical conductivity
• Flat bands
• High-pressure studies
• Magnetic phase transitions
• Magnetic susceptibility
• Nitrides
• Strongly correlated systems
• Specific heat measurements
• Susceptibility measurements
• X-ray diffraction