Low temperature C2/c and high temperature P321 modifications of Sm x Sc 4-x (BO 3) 4 solid solutions were grown from LiBO 2 –LiF flux. These borates have typical luminescence for Sm3+ containing crystals with the two strongest peaks at 602 and 645 nm, which correspond to 4G 5∕2 → 6H 7∕2 , 6H 5∕2 electron transitions. In addition, the compounds were characterized by IR and Raman spectroscopy. SHG intensity for trigonal modification was found to be three times higher than that of KDP revealing its high potential for various NLO applications. • Monoclinic and trigonal phase of Sm x Sc 4-x (BO 3) 4 crystals were grown from LiBO 2 –LiF flux. • Sm 0.78 Sc 3.22 (BO 3) 4 structure was solved. • Luminescent and absorption spectra for Sm x Sc 4-x (BO 3) 4 crystals were measured. • SHG intensities of Sm x Sc 4-x (BO 3) 4 are 2.3–3 times higher than that of KDP. [ABSTRACT FROM AUTHOR]