Abstract In the present research, β-bismuthene nanosheet (β-BiNS) is used as a base substrate to adsorb two volatile organic vapors evolved from sewer headspace, namely, benzyl alcohol (BA), and 2-methyldecalin (MD). Initially, the structural firmness of β-BiNS is established using cohesive formation energy and observed to be stable. The surface adsorption of BA and MD molecules on β-BiNS are explored with regard to the density of states, energy gap variation, adsorption energy, and charge transfer. Besides, β-BiNS exhibits chemi-resistive behavior upon adsorption and desorption of BA and MD vapors, which indicates its use as chemosensor towards toxic vapors evolved from sewer headspace.