Anisaldehyde stain is used in laboratory experiments to detect the presence of certain compounds, such as lignin and other plant materials, by producing a color reaction that helps researchers identify and analyze these substances.

In the aldol condensation between acetone and p-anisaldehyde, the p-anisaldehyde first acts as the electrophile, accepting a proton to form an enolate ion. This enolate ion then attacks the carbonyl carbon of acetone, forming a new carbon-carbon bond. The resulting aldol product undergoes dehydration to form the final α,β-unsaturated ketone.

To use the p-anisaldehyde stain in histological analysis, first prepare a solution of p-anisaldehyde in glacial acetic acid. Then, apply the stain to the tissue sample on a microscope slide and allow it to react for a specific amount of time. Rinse the slide with alcohol and water to remove excess stain. Finally, examine the stained tissue under a microscope to observe any specific structures or features.