Gas sensing materials have been widely explored recently owing to their versatile environmental and agriculture monitoring applications. The present study advocates the electronic response of Zn-decorated inorganic B 12 P 12 nanoclusters to CO 2 gas. Herein, a series of systems CO 2 −Zn−B 12 P 12 (E1−E4) are designed by adsorption of CO 2 on Zn-decorated B 12 P 12 nanoclusters, and their electronic properties are explored by density functional theory. Initially, placement of Zn on B 12 P 12 delivers four geometries named as D1−D4, with adsorption energy values of −57.12, −22.94, −21.03, and −14.07 kJ/mol, respectively, and CO 2 adsorption on a pure B 12 P 12 nanocage delivers one geometry with an adsorption energy of −4.88 kJ/mol. However, the interaction of CO 2 with D1−D4 systems confers four geometries named as E1 (E ad = −75.12 kJ/mol), E2 (E ad = −25.89 kJ/mol), E3 (E ad = −42.43 kJ/mol), and E4 (E ad = −28.73 kJ/mol). Various electronic parameters such as dipole moment, molecular electrostatic potential analysis, frontier molecular orbital analysis, Q NBO , global descriptor of reactivity, and density of states are also estimated in order to understand the unique interaction mechanism. The results of these analyses suggested that Zn decoration on B 12 P 12 significantly favors CO 2 gas adsorption, and a maximum charge separation is also noted when CO 2 is adsorbed on the Zn−B 12 P 12 nanocages. Therefore, the Zn-decorated B 12 P 12 nanocages are considered as potential candidates for application in CO 2 sensors.