Two‐dimensional materials have allowed for great advances in the biosensors field and to obtain sophisticated, smart, and miniaturized devices. In this work, we optimized a highly sensitive and selective phenol biosensor using 2D pnictogens (phosphorene, arsenene, antimonene, and bismuthene) as sensing platforms. Exfoliated pnictogen were obtained by the shear‐force method, undergoing delamination and downsizing to thin nanosheets. Interestingly, compared with the other tested elements, antimonene exhibited the highest degree of exfoliation and the lowest oxidation‐to‐bulk ratio, to which we attribute its enhanced performance in the phenol biosensor system reported here. The proposed design represents the first biosensor approach developed using exfoliated pnictogens beyond phosphorene. Biosensors based on thin nanosheets of 2D antimonene were used for phenol detection. This phenol biosensor shows enhanced analytical performance when compared to the other pnictogens in terms of linearity, sensitivity, selectivity, and reproducibility.