Pyridazine is an aromatic, heterocyclic, organic compound with the molecular formula C4H4N2.

The pyridazine structure is a popular pharmacophore which is found within a number of herbicides such as credazine, pyridafol and pyridate.

It is also found within the structure of several drugs such as cefozopran, cadralazine, minaprine, pipofezine, and hydralazine.

[4] The parent heterocycle was first prepared by oxidation of benzocinnoline to the pyridazinetetracarboxylic acid followed by decarboxylation.

A better route to this otherwise esoteric compound starts with the maleic hydrazide.