catena-Poly[[(1,10-phenanthroline-5,6-dione-κN,N')lead(II)]-μ-terephthalato-κO:O].

The Pb(II) atom in the polymeric title compound, [Pb(C(8)H(4)O(4))(C(12)H(6)N(2)O(2))](n), is chelated by the N-heterocycle, and adjacent atoms are bridged by rigid terephthalate dianions into a linear chain. The Pb(II) atom is stereochemically active in a ψ-square-pyramidal coordination geometry in which the lone-pair electrons occupy a basal site. When three other weaker Pb⋯O inter-actions are considered, the geometry is a ψ-dodeca-hedron.