The molecular structure of RN(py)quin, with R=H (1), Ph (2), and Mes (3) and the protonated complex [PhN(py)(H-quin)]BF4 (4) have been determined. Compounds 2 and 3 both crystallize in a three bladed propeller conformation. Any π–π stacking observed is dominated by quinolyl···quinolyl stacks. In contrast to analogous derivatives the acidic proton in compound 4 is chelated by the pyridyl and quinolyl heterocycles in an asymmetric fashion. Crystal data: 1 group P21/c, a = 11.571(2), b = 6.116(1), c = 15.585(3) A, β = 90.00(3)°, V = 1103.0(4) A3, Z = 4, R = 0.0440, wR 2 = 0.1064. 2 group P21/n, a = 8.081(1), b = 13.920(3), c = 27.697(6) A, β = 96.50(3)°, V = 3095(1) A3, Z = 8, R = 0.0495, wR 2 = 0.1174. 3 group P21/c, a = 12.359(3), b = 12.585(3), c = 12.457(3) A, β = 104.09(3)°, V = 1879.4(7) A3, Z = 4, R = 0.0709, wR 2 = 0.1692. 4 group P21/c, a = 15.308(3), b = 7.585(1), c = 17.227(3) A, β = 113.43(3)°, V = 1835.5(7) A3, Z = 4, R = 0.0536, wR 2 = 0.1341. The molecular structure of RN(py)quin, with R=H, Ph, and Mes, and the protonated complex [PhN(py)(H-quin)]BF4 have been determined. The presence of π–π stacking observed is dominated by quinolyl···quinolyl rather than pyridyl···quinolyl or pyridyl···pyridyl interactions.