Coordination between 5, 5′, 6, 6′-tetrahydroxyindigo (4OH-ID) and Boron tribromide unexpectedly affords a novel dynamic covalent polymer, namely P(ID-O-B), consisting of alternating indigo and indigo diradicaloid units. Catechol-boron dynamic bond plays a vital role in promoting the diradicaloid formation and stabilizing the formed diradicaloid segments. The diradicaloid segment in the polymer has a triplet ground state and a thermally-populated doublet state, which has been confirmed by EPR study. Although not conjugated, the polymer still exhibits an electric conductivity over 10−6 S/cm. SQUID study shows that the polymer is Pauli paramagnetic, indicating that metallic domain exists in this non-conjugated polymer. This diradicaloid-containing polymer is stable toward long-term storage (over 6 months) and thermal treatment over 200 ºC, but can be easily depolymerized when treated with methanol.

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