Crystal engineering of brominated tectons: N-methyl-3,5-dibromo-pyridinium iodide gives particularly short C–Br⋯I halogen bonding

The crystal matrix of N-methyl-3,5-dibromopyridinium iodide is constituted of infinite helices where the cation and the anion alternate and are bound by the second shortest reported C–Br⋯I halogen bonding. The electron poor pyridinium scaffold is particularly effective in boosting the electron acceptor ability of bromine substituents.