Two novel dimethylphenyl imidazole dicarboxylate-based lanthanide(iii)-organic frameworks, [Ln(H2DMPhIDC)3(H3DMPhIDC)]n (Ln = Eu (1), Tb (2); H3DMPhIDC = 2-(3,4-dimethylphenyl)-1H-imidazole-4,5-dicarboxylic acid) have been synthesized under hydrothermal conditions.