The ACID plots of 9 (Figure ) and 10 (Figure ) also revealed a global aromatic ring current, but showed that the current in the unsubstituted five-membered ring was significantly more pronounced than in the disubstituted ring. In fact, a closed loop of an additional local cyclopentadienyl-like circuit in the unsubstituted five-membered ring was seen in each compound. The NICS X shift above the centre of the latter was 21% higher in 9 and 13% higher in 10 (-15.7 ppm for 9 and -18.0 ppm for 10)