The single crystals of two polymorphs of LnNiGa 4 , namely, the orthorhombic α-LnNiGa 4 (Ln = Y, Gd-Yb) and, a new polymorph, the tetragonal β-LnNi 1-x Ga 4 (Ln = Tb-Er), were successfully grown by using the self-flux method. α-LnNiGa 4 (Ln = Y, Gd-Yb) is isostructural to YNiAl 4 and can be described as an edge-sharing polyhedral of Ni@Ga 7 Ln 2 (Ln = Y, Gd-Yb) along the ac-plane that is sandwiched between the square nets of the Ga atoms along the b-axis. The structure of β-LnNi 1-x Ga 4 (Ln = Tb-Er) is a distorted variant of the