2,2':6',2"-terpyridine-4,4',4"-tricarboxylic acid CAS: 216018-58-5 is N-containing tridentate ligand. It became rising in the world due to its complex with Ru(II) applied in dye-sensitized solar cell reached very high conversion efficiency (10.4%), reported by Michael Graetzel group from Swiss Federal Institute of Technology (J. Am. Chem. Soc. 2001, 123, 1613-1624).
This big event has been attracted many organic chemists focusing on synthesis of 2,2':6',2"-terpyridine-4,4',4"-tricarboxylic acid CAS: 216018-58-5. The French chemists, Jerome Husson et. al.from Universite de Frenche-Comte reported a practical synthetic route to make the ligand in larger scale, published on Natural Protocols 2014, 9(1), 21-26 (https://www.nature.com/articles/nprot.2013.162). 2-Furaldehyde CAS:98-01-1 reacts with two molecules of methyl 2-acetylisonicotinate CAS:138715-82-9 in subsequent aldol condensation, 1,4-addition, cyclization in the presence of ammonia to form the pyridine ring. Finally, oxidation under potassium permanganate to split the furan ring to get the carboxylic acid group.
UCHEM has been making this chemical with same protocols in kilograms and supplied this chemical in kilograms to Dyesol from 2011.03. to 2012.11.
With the similar protocols, UCHEM has also been making and supplying the following terpyridine derivatives in kilograms to our customers all over the world.

2,2':6',2"-Terpyridine-4'-carboxylic acid CAS:148332-36-9
Ethyl 2,2':6',2''-terpyridine-4'-carboxylate CAS:148332-31-4
2,2':6',2''-Terpyridine-4'-methanol CAS:148332-32-5
2,2':6',2''-Terpyridine-4'-carboxaldehyde CAS: 108295-45-0
4'-(4-hydroxyphenyl)-2, 2':6', 2"-terpyridine CAS: 89972-79-2
4'-(9-Anthracenyl)-2,2':6',2''-terpyridine CAS:163087-28-3
4'-(4-Methylphenyl)-2,2':6',2''-terpyridine CAS: 89972-77-0
4-[2,2':6',2"-terpyridine]-4'-yl-benzoic acid CAS: 158014-74-5
4'-(4-Bromophenyl)-2,2':6',2"-terpyridine CAS: 89972-76-9
4'-(4-Methoxyphenyl)-2,2':6',2"-terpyridine CAS: 13104-56-8
4'-Phenyl-2,2':6',2''-terpyridine CAS: 58345-97-4