From 1802 to his death, he lived in Nancy where he was named in 1807 as director of the botanical garden and member of the scientific academy of the town.

As an application of his laboratory work, it occurred to Braconnot that the "absolute tallow" (similar to stearine) from beef or sheep could be used to make candles.

In the domain of plant chemistry, Braconnot contributed to the isolation and the description of several compounds, most of which were shown later to be mixtures of simpler products.

In 1819, he published a memoir describing for the first time the conversion of wood, straw or cotton into a sugar by a sulfuric acid treatment.

The name glucose was proposed 24 years later by Dumas for a sugar similarly obtained from starch, cellulose, or honey.

Furthermore, reacting concentrated nitric acid on wood or cotton, Braconnot obtained a flammable product, xyloïdine (a precursor of collodion and nitrocellulose), which could be transformed into a vitreous varnish.