An unprecedented polyoxometalate-based 1D double chain compound with opposite charges enables conductivity improvement.

A POM-based one-dimensional (1D) chain compound, {BW12O40[Cu(2,2′-bipy)2]2[Cu(2,2′-bipy)(H2O)]}{BW12O40[Cu(2,2′-bipy)2][Cu(2,2′-bipy)(H2O)2]}·7H2O, has been synthesized and structurally characterized, which represents an unprecedented 1D double chain structure with opposite charges. In contrast to common POMs, this compound exhibits a relatively high electrical conductivity of 1.17 × 10−9 S cm−1 at 25 °C. In addition, its semiconducting properties have also been investigated by application of photoelectrochemical sensing of H2O2.