噻二唑是唑类化合物的一个亚家族。在结构上，它们是五元杂环化合物，含有两个氮原子和一个硫原子，以及两个双键，形成芳香环；噻二唑的名称来源于Hantzsch-Widman命名法。根据杂原子的相对位置，存在四种可能的结构；这些形式不相互转化，因此是结构异构体而不是互变异构。这些化合物本身很少被合成，并且没有特别的用途，然而，将它们作为结构基序的化合物在药理学中相当常见。
4,7-Dibromo-5,6-dinitrobenzo[c][1,2,5]thiadiazole
4,7-Dibromo-5,6-dimethylbenzo[c][1,2,5]thiadiazole
7-Bromo-2,1,3-benzothiadiazole-4-carbonitrile
2-((7-Bromobenzo[c][1,2,5]thiadiazol-4-yl)methylene)malononitrile
7-Bromobenzo[c][1,2,5]thiadiazole-4-carboxylic acid
2-Amino-5-methyl-1,3,4-thiadiazole
2-(Chloromethyl)-5-methyl-1,3,4-thiadiazole
(5-Methyl-1,3,4-thiadiazol-2-yl)methanol
2-Chloro-5-methyl-1,3,4-thiadiazole
Lithium 5-methyl-1,3,4-thiadiazole-2-carboxylate
Ethyl 5-methyl-1,3,4-thiadiazole-2-carboxylate
2-Bromo-5-methyl-1,3,4-thiadiazole
5-Methyl-1,3,4-thiadiazole-2-carbaldehyde
2-Chloro-N-(5-methyl-1,3,4-thiadiazol-2-yl)acetamide
2-Methyl-5-(methylsulfanyl)-1,3,4-thiadiazole
2-Methoxy-5-methyl-1,3,4-thiadiazole
Methyl 4-bromo-1,2,5-thiadiazole-3-carboxylate
1,2,5-Thiadiazole-3-carboxylic acid
3,4-Dichloro-1,2,5-thiadiazole
4-Amino-1,2,5-thiadiazole-3-carboxamide
4-Amino-1,2,5-thiadiazole-3-carboxylic acid
Methyl 4-amino-1,2,5-thiadiazole-3-carboxylate
(Z)-2-(5-Amino-1,2,4-thiadiazol-3-yl)-2-(ethoxyimino)acetic acid
5-Chloro-3-methyl-1,2,4-thiadiazole
5-(Boc-amino)-1,2,4-thiadiazole
5-Amino-3-methyl-1,2,4-thiadiazole
5-Bromo-1,2,4-thiadiazole
3-(Methylthio)-1,2,4-thiadiazol-5-amine
5-Bromo-3-methyl-1,2,4-thiadiazole
5-Amino-1,2,4-thiadiazole
