In the title compound, [Cu(C(7)H(5)O(3))(2)(C(5)H(5)N)(2)], the Cu atom is located on an inversion center and is coordinated by the N atoms of the two pyridine ligands, trans to each other, and to the carboxyl-ate O atoms of two bidentate 4-hy-droxy-benzoate ligands [Cu-O = 1.9706 (10) and 2.5204 (11) Å]. Hydrogen bonding between hy-droxy H and carboxyl-ate O atoms results in a layer structure parallel to the ab plane.
The structure of the dinuclear title complex, [Cu(2)(C(5)H(9)O(2))(4)(C(5)H(5)N)(2)], represents a monoclinic polymorph of the previously reported triclinic form [Blewett et al. (2006 ▶). Acta Cryst. E62, m420-m422]. Each carboxyl-ate group is bidentate bridging and the distorted octa-hedral geometry about each Cu(II) atom is completed by a pyridine N atom and the other Cu atom [Cu⋯Cu = 2.6139 (7) Å]. In the crystal, mol-ecules are connected into supra-molecular chains via π-π inter-actions formed by the pyridine rings [centroid-centroid distance = 3.552 (3) Å] and these are connected into a two-dimensional array in the ac plane by C-H⋯π contacts. One of the tert-butyl groups is disordered over two orientations in a 0.734 (6):0.266 (6) ratio.