In summary, our study demonstrates the effectiveness of using a high refractive index as a proxy for a high SHG coefficient. We develop two separate ML models: one for predicting high refractive indices and another for Vickers hardness. Subsequently, we identify potential NLO materials from the largely unexplored OQMD database, focusing on properties such as non-centrosymmetricity, high refractive index, hardness value, and bandgap.