2,4 bis(2-hydroxy 4-diethylaminophenyl)-1,3-cyclobutadienediylium 1,3-diolate;

bis(4-diethylamino-2-hydroxyphenyl)squaraine;

1-(4-Diethylamino-2-hydroxyphenyl)-3-(4-diethylimmonium-2-hydroxycyclohexa-2,5-dien-1-ylidene)-2-oxo-cyclobuten-4-olate;