This present paper reports the synthesis and environmental applications of conducting polyaniline-Sn(IV)tungstomolybdate nanocomposite. The material was synthesized via a very simple chemical route and characterized by using various instrumental techniques. Physicochemical properties, pH titrations, and elution behavior were studied to exploit the ion-exchange capability of nanocomposite. Electrical conducting studies were performed by using 4-in-line-probe (Direct Current) electrical conductivity measuring instrument. The conductivity of the material was found to be in the range of semiconductor’s. Distribution coefficient values were measured in demineralized water and varying concentration of dimethyl sulfoxide, and on the basis of partition coefficient values, the material was found to be selective for Pb2+ ions. This nanocomposite material has been fruitfully applied for the treatment of heavy metals from synthetic mixture and industrial waste water samples. The limit of detection and the limit of quantification for Pb2+ ion were found to be 0.97 and 3.24 μg L−1, respectively. The material was also tested for antimicrobial activity, and it was found that besides its use as an ion-exchange material, polyaniline-Sn(IV)tungstomolybdate is successfully used as an antimicrobial agent and as well as semiconductor.