AbstractA new enantioselective potentiometric sensor containing R‐type chiral porous organic cage CC9 as the chiral selector was designed for the assay of 2‐aminobutanol. Optimized membrane electrodes displayed a linear dynamic range from 10−3 ~ 10−1 mol·L−1 with a detection limit of 2.5 × 10−4 mol·L−1 and a Nernstian response of 27 ± 0.5mV·decade−1 toward S‐2‐aminobutanol within the pH range 7.0–10.0. The potentiometric enantioselectivity coefficient ( ) of this sensor was −1.333, indicating that the porous organic cage‐based electrode exhibited good discrimination toward S‐2‐aminobutanol over R‐2‐aminobutanol.