Organic nonlinear optical co-crystals 2-aminopyrimidine benzoic acid (2APB) and 2-aminopyrimidine succinic acid (2APS) have been successfully grown by slow solvent evaporation method at room temperature. The structural characterization of the grown crystals was carried out by single crystal X-ray diffraction. Fourier transform infrared spectroscopy (FT-IR) and FT-Raman spectra of the grown crystals are recorded and the observed vibrational frequencies are assigned. The hybrid computational calculations are carried out by Hartree–Fock (HF) and density functional theory (DFT) (3-parameter, Lee-Yang-Parr (B3LYP)) methods with 6-311[Formula: see text]G(d,p) basis sets and the corresponding results are tabulated. The geometrical parameters of the molecules also have been analyzed. The computed vibrational spectra were compared with experimental result which shows appreciable agreement. The chemical hardness, electronegativity, chemical potential and electrophilicity index were determined by highest occupied molecular orbital–lowest unoccupied molecular orbital (HOMO–LUMO) plot. The grown crystals were subjected to population analysis, thermal, linear and nonlinear optical studies of materials. The calculated second-order hyperpolarizability values of these materials are nearly two to four times that of urea.
