The antiaromatic character of the synthesized S2O2Iphs was evaluated using 1 H NMR spectroscopy (Figure ). The β-protons of both 1a and 1b exhibited characteristic upfield-shifted singlets at approximately 3.35 ppm, indicating strong paratropic ring currents and pronounced antiaromaticity. In contrast, the corresponding signals for 1c appeared at 4.26 and 4.16 ppm, which were significantly downfield-shifted compared to those of 1a and 1b. This suggests a weaker paratropic ring current, indicating diminished antiaromaticity in 1c relative to 1a and 1b. Another likely contributing factor is the varying degrees of the shielding effects of the aromatic substituents. Therefore, we conducted a comprehensive investigation using various antiaromaticity indices to fully evaluate these effects.