5-(4-Chlorophenyl)-3-(2,4-dimethylthiazol-5-yl)-1,2,4-triazolo[3,4-a]isoquinoline

In the title molecule, C21H15ClN4S, the triazoloisoquinoline ring system is approximately planar, with an r.m.s. deviation of 0.054 (2) Å and a maximum deviation of 0.098 (2) Å from the mean plane for the triazole ring C atom that is bonded to the thiazole ring. The thiazole and benzene rings are twisted by 66.36 (7) and 56.32 (7)°, respectively, with respect to the mean plane of the triazoloisoquinoline ring system. In the crystal structure, molecules are linked by intermolecular C—H...N interactions along the a axis. The molecular conformation is stabilized by a weak intramolecular π–π interaction involving the thiazole and benzene rings, with a centroid–centroid distance of 3.6546 (11) Å. In addition, two other intermolecular π–π stacking interactions are observed, between the triazole and benzene rings and between the dihydropyridine and benzene rings [centroid–centroid distances = 3.6489 (11) and 3.5967 (10) Å, respectively].