1H-1,2,4-Triazole-3-thiol is a mercapto-substituted 1,2,4-triazole ligand and exhibits tautomerism in solution. 1H-1,2,4-Triazole-3-thiol forms novel luminescent polymers with cadmium(II) salts. 1H-1,2,4-Triazole-3-thiol undergoes regioselective S-alkylation to form a series of S-substituted derivatives.