1‐Acetyl‐, 1‐propionyl‐ and 1‐phenyl‐3,5‐diaryl‐2‐pyrazolines have been synthesized by the reaction of the appropriate α,β‐unsaturated ketones with hydrazine or phenylhydrazine in hot acetic acid or propionic acid. Structures of all new 2‐pyrazolines 16‐40 have been elucidated by microanalyses, 1H and 13C nmr spectroscopies.