A novel series of quinazoline clubbed thiazoline derivatives was rationally designed and synthesized. The newly synthesized compounds were evaluated for in vitro dipeptidyl peptidase IV (DPP‐4) inhibitory activity. Compounds that showed good to moderate activity were compared using linagliptin as standard. Compound 4x (IC₅₀ = 1.12 nM) exhibited the most promising results. The special chemical feature of compound 4x also imparts good inhibition selectivity for DPP‐4 over DPP‐8/9. Moreover, docking of compound 4x into the active site of DPP‐4 illustrates its possible binding interactions.