In this research, we explored black phosphorene nanotube’s ability to the detection of DDT (dichlorodiphenyltrichloroethane) and heptachlor present in the polluted water. The formation energy of the designed black phosphorene nanotube delineates its stable configuration. The adsorption properties for the target molecules assimilation over black phosphorene nanotube have been scrutinised concerning adsorption energy, which shows the physisorption type of adsorption on the black phosphorene nanotube. The electronic characteristics of black phosphorene nanotube constituted by the energy band specifications (spectrum of energy bands and PDOS maps) and the contours of electron density differences are visualised for the pristine and adsorption complexes. Those attributes validate the change in the electronic properties of black phosphorene nanotube following the adsorption. Moreover, the variation in the energy gap of black phosphorene nanotube, which is perceived upon adsorption of DDT and heptachlor shows chemi-resistive nature. The calculated adsorption energy, Bader charge transfer, and electron density difference of black phosphorene nanotube owing to adsorption of target molecules suggest the use of black phosphorene nanotube as a chemical sensor for DDT and heptachlor.