The formation of the complete series of phenylazophenyl(C,N )tellurium(II) halides (fluoride, chloride, bromide and iodide) is described in this paper. The monoiodide arose from the reaction of the monobromide and diiodine. The new monoclinic modification of phenylazophenyl(C,N )tellurium(II) chloride (RTeCl) contains only one independent molecule in the unit cell, whereas a previously reported modification contains two molecules per unit cell, and is triclinic. The bond lengths Te-N(2) were in the range that were expected for a secondary bonding interaction, i.e., 2.210(7)-2.252(8) 9. On comparison of the Te-N(2) bond length for the series of compounds, it was noted that as a more electronegative atom was attached to the Te atom, the stronger the secondary interaction became. The monofluoride, synthesised by two independent methods, is an orange liquid which is characterised by 1 2 5 Te and 1 9 F NMR.