Acridinium 3,5-dichlorosalicylate (ACHB) has been synthesised and crystallised at room temperature. ACHB was characterised by single crystal X-ray diffraction. The crystal structure of ACHB displays N–H⋯O, C–H⋯O, O–H⋯O (intramolecular) and π … π interactions. The presence of chlorine atoms greatly influence the supramolecular organisation of ACHB by C–H⋯Cl and C–Cl … π interactions to form a network. The role of chlorine interactions on the crystal structure is explained through structural analysis. This manuscript explains the influence of chlorine atom on the crystal structure and how it affects the stacking interactions. The proportion of intramolecular interactions involving chlorine was identified by using Hirshfeld surface analysis which is found to be 26.9%. The percentage of interactions clearly exposes the contribution of chlorine atom on defining the directionality of the non-covalent interactions involved in ACHB. The molecular structure of ACHB was optimised by DFT calculations at B3LYP/6-311G++(d,p) level of theory. Theoretical UV spectral analysis was carried out for ACHB using TD-DFT calculations in methanolic phase. Electrostatic potential, NBO analysis and Mulliken plot reveals the nature of the molecular structure. Static and frequency dependent hyperpolarizability were calculated at the same level of theory. The chlorine interactions involved in ACHB influence the hyperpolarizability on applied frequency at 1064 nm.