Compiled from the Note Identification Project Thread:
Quinoline – Amazing. Took me by complete surprise. Dry, pleasant leather. (I think this is what goes into Azuree.) Salty in character, non-sweet dry herbs, a bit spicy like cumin. Quinoline and castoreum are both leather scents, but they are quite different. Quinoline impresses me as dry, while castoreum is more of a wet, animalic leather, like the pelt of an animal, or a tack room in a horse barn
Quinoline: odd, dark, slightly bitter leather - also a little salty with a kinda petrol-y smell to it. I resniffed Alliage to compare and I think I do smell quinoline in Alliage.
(Isobutyl) Quinoline - 2% dilution in carrier oil: dry, green, bitter, rubbery fake leather. How much did Mdame Cellier pour into Bandit and Jolie Madame? To my nose, at least 20%! I have a couple of ideas myself on mixing with this note.