A new potential toxaphene congener 3-endo,5-endo-dichloro-7,7-bis-chloromethyl-4-dichloromethyl-tricyclo[2.2.1. 0 2 , 6 ]heptane 2 has been isolated from reaction mixture obtained by the chlorination of 2-exo,10,10-trichlorobornane 1. The X-ray structural analysis of 2 revealed an unusual tricyclic structure, where the two chlorine atoms occupying endo-positions are in close spatial proximity with each other and near to the neighbouring CHCl 2 group. Further, it revealed that the symmetry of the molecule is distorted. The 1 H and 1 3 C NMR spectra of 2 have been assigned by means of 1 H, 1 H double-quantum filtered correlation spectroscopy (DQF COSY), PFG 1 H, 1 3 C HMQC (pulsed field gradient heteronuclear multiple-quantum coherence), 1 H, 1 3 C heteronuclear multiple bond correlation (HMBC) experiments, and computer aided 1 H NMR spectral analysis. The asymmetry of 2 is also discernible on the 1 H NMR parameters. In addition, gas chromatographic (GC) properties and electron impact (EI) mass spectrum of 2 has been studied. Ab initio Hartree-Fock (HF) method with the basis set 6-31G(d) has been used for the optimization of the equilibrium geometry and calculation of total energy for 2. The optimized geometry is in good agreement with the crystal structure. According to the rotation energy profile calculated at the HF/6-31G(d) level, rotation of the chloromethyl and dichloromethyl groups are highly unlikely at the room temperature.