Emergent interlayer magnetic order via strain-induced orthorhombic distortion in the <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mn>5</mml:mn><mml:mi>d</mml:mi></mml:mrow></mml:math> Mott insulator <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:msub><mml:mi>Sr</mml:mi><mml:mn>2</mml:mn></mml:msub><mml:msub><mml:mi>IrO</mml:mi><mml:mn>4</mml:mn></mml:msub></mml:mrow></mml:math>

We report a La2CuO4-like interlayer antiferromagnetic order in Sr2IrO4 films with large orthorhombic distortion (> 1.5%). The biaxial lattice strain epitaxial heterostructures of Sr2IrO4/Ca3Ru2O7 lowers the crystal symmetry from tetragonal (C4) to (C2), guiding Ir 5d Jeff = 1/2 pseudospin moment parallel elongated b-axis via magnetic anisotropy. From resonant X-ray scattering experiments, we observed an film whose stacking pattern is inverted that crystal. This similar La2CuO4, implying asymmetric exchange interaction along and b-directions exceeds anisotropic pseudo-dipolar interaction. Our result suggests strain-induced can provide delicate knob for tuning long-range quasi-two-dimensional systems by evoking competition between coupling