Abstract: A new complex named HMNd has been basically designed by doping rare-earth neodymium metal inside the hexamine surface HM. Density functional theory (DFT) calculations were carried out using B3LYP functional with split basis set GENECP to examine their geometrical, electronic, and non-linear optical properties of newly designed complex HMNd. After getting stable geometry of HMNd, its optoelectronic properties were compared with pure HM surface to check the influence of doping. HMNd revealed the obvious reduction in band gap energies from 8.4 eV (HM) to 1.79 eV (HMNd) as confirmed through DOS analysis. The highest hyperpolarizability and linear isotropic polarizability values of 6.8 × 105 a.u and 262.81 a.u respectively are perceived in HMNd. Electronic and thermodynamic stability of the designed complex has been confirmed through their vertical ionization and interaction energies. As revealed through the UV–visible analysis, doping with neodymium metal (HMNd) shifts the absorption to IR region with λmax of 2699.63 nm which leads towards the production of new materials. These upshots highlight the adequacy of designed complex providing gateway for designing new IR NLO materials in laser frequency conversion technology having usages in versatile fields.