Given the presence of the CN radical, a high multi-reference character was previously noted, which presents a high Q1 diagnostic, 18 0.068 and 0.033 for the CN radical and the saddle point, respectively. The Q1 diagnostic in QCISD(T) calculations is the equivalent to the T1 diagnostic in CC calculations. In the original paper it was reported that in general the Q1 diagnostic overestimates the multi-reference character, Q1 > T1, which demonstrates that as the nondynamical correlation becomes more important, the QCISD results deteriorate faster than the CCSD ones. It is known that T1 values greater than 0.02 for closed-shell or 0.045 for open-shell systems suggest that a multireference method might be needed. In the present work, based on the saddle point geometries optimized at the CCSD(T)/cc-pVTZ level, the T1 diagnostic gives values of 0.051 for the CN radical and 0.029 for the saddle point, showing that a single-reference method could be suitable, although obviously it is a limit case.