Dinicotinic acid (pyridine-3,5-dicarboxylic acid) is a heterocyclic organic compound, more precisely a heteroaromatic.

It is one of many pyridinedicarboxylic acids and consists of a pyridine ring carrying to carboxy groups in the 3- and 5-positions.

[2][3] The acid is sparingly soluble in water and ether.

Its melting point of 323 °C is the highest among pyridinedicarboxylic acids.

Upon heating, it decarboxylates and decomposes to nicotinic acid:[4]