The crystallization mechanisms of a series of fourteen 7-chloro-4-substituted-quinolines (substituents: ( 1 ) OCH 3 , ( 2 ) OCH 2 CH 3 , ( 3 ) OCH 2 CH&z.dbd;CH 2 , ( 4 ) O(CH 2 ) 2 OH, ( 5 ) O(CH 2 ) 3 OH, ( 6 ) NH(CH 2 ) 2 CH 3 , ( 7 ) NH(CH 2 ) 3 CH 3 , ( 8 ) NH(CH 2 ) 2 OH, ( 9 ) NHCH(CH 2 CH 3 )CH 2 OH, ( 10 ) NH(CH 2 ) 2 Cl, ( 11 ) NHN&z.dbd;CH(C 6 H 5 ), ( 12 ) NHN&z.dbd;CH(2-FC 6 H 4 ), ( 13 ) NHN&z.dbd;CH(3-FC 6 H 4 ), and ( 14 ) NHN&z.dbd;CH(4-FC 6 H 4 )) were proposed based on a retrocrystallization approach using the supramolecular cluster as demarcation. Crystallization mechanism stage parameters - N CG % and NG/NC - were determined. The 4-substituents present in quinolines caused six different mechanisms, starting from the monomers in solution to dimers, 1D nuclei, and 2D nuclei ( 6 , 11 , 12 ); 2D nucleus formation ( 5 ); 1D nuclei to 2D nuclei ( 7 , 9 ); concomitant dimers and 1D nuclei to a 3D crystal ( 8 ); 1D nuclei directly to a 3D crystal lattice ( 1-4 , 10 , 14 ), and dimers to 2D nuclei and then to a 3D crystal ( 13 ). Analysis of G AI showed atom atom intermolecular interactions in the proposed first nuclei for compounds 4 and 5 . The nucleation process inferred in the solid state was partially confirmed during the formation of the proto-crystal in solution due to the changes of the hydrogen chemical shift in variable-concentration 1 H-NMR experiments. Results revealed that the size of the alkyl chain and the presence of different functional groups in the 4-substituents influenced the crystallization process. The crystallization mechanisms of a series of fourteen 7-chloro-4-substituted-quinolines were proposed based on a retrocrystallization approach using the supramolecular cluster as demarcation.