Presented　herein　are　two　luminescent　magnesium　coordination　polymers　(Mg-CPs),　namely　[Mg-2(H2O)(2)(2-NDC)(4)(1,10-phen)(2)]　(1)　and　[Mg-2(H2O)(1,4-NDC)(2)(1,10-phen)]　(2),　in　which　2-NDCH　=　2-naphthalenecarboxylic　acid,　1,4-NDCH2　=　1,4-naphthalene　dicarboxylic　acid,　and　1,10-phen　=　1,10-phenanthroline.　Based　on　the　mixed　ligands,　the　title　compounds　exhibit　linker-based　photoluminescence　(PL)　properties　thanks　to　the　unique　configuration　of　the　Mg2+　ions.　The　two　compounds　show　interesting　dual　emission　on　excitation　of　the　different　luminophores　of　the　mixed　linkers.　In　particular,　the　emissions　of　compound　2　could　be　tuned　from　green　to　yellow　simply　by　varying　the　excitation　energies.　Furthermore,　2　could　be　excited　by　using　a　commercial　lambda　=　450　nm　blue　LED　chip　to　generate　white-light　emission,　which　allows　the　fabrication　of　a　white-light-emitting　diode　(WLED)　with　20　lm　W-1　luminous　efficacy.　This　work　may　provide　a　new　method　for　designing　tunable　PL　CPs　by　using　the　low-cost　and　abundant　magnesium　ion.