Adsorption of cyanogen molecule on the surface of pristine and Sc-doped B12N12 nanocage is scrutinized using at DFT calculations to investigating its potential as chemical nanosensors. The results show that cyanogen is weakly adsorbed on the pristine B12N12 and consequently its electrical properties are changed insignificantly. In order to improve the properties of the nanocage sensor, Sc doping process was investigated. The obtained results show that doping process changes electrical properties of B12N12 dramatically. Furthermore, adsorption of the cyanogen on the exterior surface of Sc-doped B12N12 proves strong physisorption with Eads equal to -73.20 kJ mol-1. UVVis spectra display new absorption peaks confirming sensing ability of Sc-doped B12N12 for detection of the cyanogen molecule. Desired nanosensor has short recovery time because adsorption energy of NCCN molecule is not too large. It is expected that Sc-doped B12N12 acts as new potential nanosensor to detect toxic cyanogen molecule.