The comparative study of the structure and photoluminescence (PL) properties of the Eu 3 and Tb 3 activated Na 3Ln(BO 3) 2, with Ln=Y, Gd, showed the important role of the host lattice structure upon PL. Higher emission intensities of Eu 3 and Tb 3 are observed for Na 3Gd(BO 3) 2 than for Na 3Y(BO 3) 2, through direct Eu 3 excitation at 395 nm for Eu 3 doped borates, and through Gd 3 excitation around 280 nm for Tb 3 doped borates. This higher performance for Na 3Gd(BO 3) 2 is due to the less regular environment of Eu 3 (Tb 3) in the Gd sites than in the Y sites and to energy transfer from Gd 3 to Eu 3(Tb 3). The smaller critical concentration in Na 3Ln 1-xTb x(BO 3) 2 observed for Ln=Gd, x=0.5, compared to x=0.6 for Ln=Y, is explained by shorter Ln-Ln distances (4.11 Å for Gd-Gd vs. 4.59 Å for Y-Y). Both Na 3Y 0.4Tb 0.6(BO 3) 2 and Na 3Gd 0.5Tb 0.5(BO 3) 2 show intense green emission under UV excitation. © 2012 Elsevier Inc.