A new type of nonlinear optical crystal DMNC was synthesized and grown by introducing a naphthalene ring and methoxy on the chalcone structure. Single crystal diffraction analysis suggests that DMNC crystal is in the Pna2₁ space group and belongs to a non-centrosymmetric structure, which is the basis for the high non-linearity of DMNC. Experimental results reveal that the DMNC crystal is a phase-matched material with a maximum SHG signal 2.3 times higher than that of the benchmark OH1 crystal. The conclusion is that the design strategy of introducing the naphthalene ring and methoxy greatly enhances the macroscopic nonlinearity of the DMNC crystal. Characterization of the optical, thermal and electrical properties of DMNC shows its broad transparency, high melting point, small dielectric constant and stability at high frequencies, providing good conditions for its application in non-linear optical devices.