1,8‐Bis(dimethylaminomethyl)naphthalene bis(squaric acid) dihydrate

In the crystal structure of the title compound, bis[(1-dimethylamino-8-naphthyl)dimethylammonium] 3,4-dihydroxy-3-cyclobutene-1,2-dionate(2-) dihydrate, 2C 16 H 23 N 2 + .C 4 O 4 2- .2H 2 O, 1,8-bis(dimethylaminomethyl)naphthalene acts as a proton sponge by accepting protons from squaric acid. The protons form disordered asymmetric [N-H...N] + hydrogen bonds. The crystal water is hydrogen bonded to the squarate anion in a 2:1 cluster.