1,3,4-THIADIAZOLE, 2,5-BIS(4-PYRIDYL)- 2,5-Bis(4-pyridyl)-1,3,4-thiadiazole 54010-21-8 Pyridine, 4,4'-(2,5-dihydro-1,3,4-thiadiazole-2,5-diyl)bis-