“…[ 6 ] Among them, selenides normally exhibit wider IR transparent regions, larger SHG responses, and lower melting points, but smaller band gaps than sulfides. [ 7 ] Over the past decades, a plenty of selenides with good NLO properties like LiGaSe 2 , [ 8 ] α ‐BaGa 4 Se 7 , [ 9 ] β ‐BaGa 4 Se 7 , [ 10 ] β ‐BaGa 2 Se 4 , [ 11 ] Li 2 ZnMSe 4 (M = Ge, Sn), [ 12 ] Li 2 CdMSe 4 (M = Ge, Sn), [ 13 ] Li 2 In 2 MSe 6 (M = Si, Ge), [ 14 ] Na 4 MgM 2 Se 6 (M = Si, Ge), [ 15 ] BaGa 2 MSe 6 (M = Si, Ge), [ 16 ] γ ‐NaAsSe 2 , [ 17 ] Na 6 MSe 4 (M = Zn, Cd), [ 18 ] CsM 3 Se 6 (M = Ga/Sn, In/Sn), [ 19 ] and AgLiGa 2 Se 4 [ 20 ] have been designed and synthesized successfully. However, to enhance the LIDT, the band gaps in selenides are still highly expected to be further improved.…”