In this report, we have presented the theoretical investigation of anilinium hydrogen oxalate hemihydrate – an organic crystalline salt. The molecular geometry, as well as the vibrational parameters, are calculated theoretically with the aid of density functional theory using B3LYP/6-311++G (d,p) basis set using Gaussian 09 program. Infrared and Raman spectrum are depicted from the calculated intensities. Frontier molecular orbital analysis confirms the charge transfer that occurs within the molecule and also other electronic parameters viz. softness (S), hardness (η), electron affinity (A), ionization potential (I), chemical potential (μ), electrophilicity index (ω), electronegativity (χ), have been calculated. Hyper conjugative interactions as well as charge delocalization is analyzed with the help of natural bonding orbital analysis. The first order hyper polarizability as well as dipole moment are calculated using B3LYP/6-311++G(d,p) basis set. Further molecular electrostatic potential describes the presence of inter and intra molecular interactions that occurs within the molecule.