Abstract: | The structure of poly3‐(4‐amino‐2‐methylpyrimidin‐1‐ium‐5‐yl)methyl]‐5‐(2‐hydroxyethyl)‐4‐methylthiazolium octa‐μ‐bromo/chloro(4.4/3.6)‐tricadmate(II)], {(C12H18N4OS)Cd3 Br4.41Cl3.59]}n consists of hydrogen‐bonded thiamine molecules and polymeric cadmium bromide/chloride anions in an organic–inorganic hybrid fashion. The one‐dimensional anion ribbons are formed by edge‐sharing octahedra and vertex‐sharing tetrahedra. Thiamine molecules adopting the S conformation are linked to anions via three types of interactions, namely an N(amino)—H⋯anion⋯thiazolium bridging interaction, an N(pyrimidine)—H⋯anion hydrogen bond and an O(hydroxy)—H⋯anion hydrogen bond. |