The title compounds 1-(4-aryl-5-triazolyl-2-thiazolyl)-3,5-diaryl-2-pyrazoline derivatives (3a–c) were synthesized by reacting 3,5-diaryl1-thiocarbamoyl -2-pyrazoline 1 with 2-bromo-1-aryl-2-(1H-1,2,4-triazol-1-yl) ethanones 2 in boiling ethanol. Their structures were characterized by IR, 1H-NMR, MS spectroscopic data and elementary analyses. The structure of compound (3a), C26H18Cl2N6S, was conclusively established with X-ray crystal structure analysis. It crystallizes in the Orthorhombic space group Pna2(1), with a = 17.8160(5), b = 18.9125(7), c = 14.7926(4), α = 90°, β = 90°, γ = 90°and Dc = 1.379 mg/m3 for Z = 8, V = 4984.3(3) A, μ(Mo–Kα) = 0.372 mm, λ = 0.71070 A, the final R = 0.0527 and wR = 0.1307 for 43309 observed reflections with I > 2σ(I). The structure is stabilized by weak C–H···N intramolecular hydrogen bonds and C–H···Cg p-ring intermolecular interactions and gives support to molecular packing stability in the unit cell. The title compounds 1-(4-aryl-5-triazolyl-2-thiazolyl)-3,5-diaryl-2–pyrazoline derivatives (3a-c) were synthesized by reacting 3,5-diaryl1-thiocarbamoyl-2- pyrazoline 1 with 2-bromo-1-aryl-2-(1H-1,2,4-triazol-1-yl) ethanones 2. Their structures were characterized by IR, 1H-NMR, MS spectroscopic data and elementary analyses. The structure of compound (3a) was conclusively established with X-ray crystal structure analysis.