In this paper, synthesis, single-crystal X-ray structure, Hirshfeld and DFT studies of 1,8-dichloro-9,10-dihydro-9,10-ethanoanthracene-11-carboxylic acid are discussed. Different intermolecular contacts affecting the crystal stability are studied using Hirshfeld calculations. The H…Cl and O…H contacts are the most significant, showing corresponding interaction distances of 2.731 Å (Cl2…H10) and 1.681Å (H1…O1), 2.328 Å (O1…H13), 2.510 Å (O1…H12) based on Hirshfeld calculations. DFT calculations are carried out to study the electronic behavior, as well as the 1H- and 13C-NMR spectra of the synthesized compound. The computed NMR chemical shifts show excellent correlation with the experimental data (R2 = 0.9884–0.9705).