The most important result of Fig. is the almost perfect correlation between the HF HOMO-LUMO gap and the ST gap. The 4n/4n+2 alternancy of the HOMO-LUMO gap is a clear remnant of the well-known alternancy of cyclic polyenes. Indeed, in cyclic polyenes, either at the Hückel or HF level, the HOMO-LUMO gap, sizable for 4n+2 rings, vanishes for 4n rings. In (CN) x rings a splitting of the HOMO-LUMO gap is found also in 4n rings, but it stays lower than for 4n+2 rings (see ESI, Fig. ). In all cases, the HOMO-LUMO gap reduces upon increasing the ring dimension.