Reactions in water between the sodium salt of benzene-1,2,4,5-tetracarboxylic acid (H(4)btec) and lanthanide ions (Sm-Dy) led to a series of isostructural lanthanide-based coordination polymers with the general chemical formula [Ln(4)(btec)(3)(H2O)(12)20H(2)O](infinity) with Ln = Sm-Dy. The family has been structurally characterized. From a luminescent point of view, the heterodinuclear strategy has been successfully applied and allows significant brightness enhancement (+35%) and color tuning from green to yellow to orange to red.