The title compound, C(11)H(9)F(3)NO(+)·ClO(4) (-)·C(11)H(8)F(3)NO or [(C(11)H(8)F(3)NO)H(C(11)H(8)F(3)NO)]ClO(4), contains two 8-(2,2,2-trifluoro-eth--oxy)quinoline molecules, one of which combines a proton from perchloric acid to form the corresponding quinolinium cation. The quinolinium and quinoline rings form a cationic unit via an inter-molecular N-H⋯N hydrogen bond. The heterocyclic units are almost perpendicular to each other [inter-planar angle 86.97 (6)°]. In the crystal, each perchlorate anion bridges two adjacent cationic units and creates a chain by a combination of C-H⋯O hydrogen bonds. Two inversion-related chains associate into a mol-ecular column by π-π stacking inter-actions between the quinolinium rings. The perpendicular and centroid-centroid distances between adjacent quinolinium rings are 3.501 (3) and 3.634 (9) Å, respectively. The molecular column is linked to its neighbors, creating a two-dimensional network via the weak π-π stacking between the quinoline rings [perpendicular and centroid-centroid separations 3.340 (4) and 4.408 (4) Å, respectively]. Finally, a three-dimensional framework is formed by a combination of intermolecular C-F⋯π contacts. One -CF(3) group is disordered over two positions of equal occupancy.