The well-known nucleus-independent chemical shift (NICS) essentially correspond to the value of ICSS at a featured point. The negative of magnetic shielding tensor component perpendicular to ring plane at 1 Å above ring center, namely NICS ZZ (1), is a widely used and accepted method for measuring aromaticity of cyclic molecules. The NICS ZZ (1) of C 18 Br 6 was calculated to be -5.0 ppm, which is significantly smaller than the corresponding value for C 18 (-23.7 ppm) and similar to that of another precursor C 18 (CO) 6 (-5.4 ppm). So, it can be inferred that the aromaticity of C 18 Br 6 should be comparable with that of the C 18 (CO) 6 , but much weaker than that of the C 18 . This can be rationalized by the fact that C 18 has two sets of global π-electron conjugated systems, while the π in -conjugations of C 18 Br 6 and C 18 (CO) 6 are blocked due to the presence of substituents.