Tetra-kis[μ-2-(3,4-dimeth-oxy-phen-yl)acetato]-κO,O:O;κO:O,O;κO:O-bis-{[2-(3,4-dimeth-oxy-phen-yl)acetato-κO,O](1,10-phenanthroline-κN,N')erbium(III)}.

In the dimeric centrosymmetric title complex, [Er(2)(C(10)H(11)O(4))(6)(C(12)H(8)N(2))(2)], the Er(III) ion is nine-coordinated by five 2-(3,4-dimeth-oxy-lphen-yl)acetic acid (DMPA) ligands via seven O atoms and two N atoms from a bis-chelating 1,10-phenanthroline (phen) ligand in a distorted tricapped trigonal-prismatic geometry. The DMPA ligands are coordinated to the Er(III) ion in bis-chelate, bridging and bridging tridentate modes. Relatively weak intra-molecular C-H⋯O inter-actions reinforce the stability of the mol-ecular structure. Inter-molecular C-H⋯O inter-actions are also observed.