The adducts of Co, Ni, Cu, Zn and Pb saccharinates with 2,2'-bipyridine were synthesized and their thermal behaviour in the 20–1000°C temperature interval in a static air atmosphere was investigated. Regardless of the coordination, the decomposition starts with dehydration and proceeds with removal of the bipyridine ligand(s). The resulting metal(II) saccharinates adopt characteristic two-step decomposition, the first step being the SO2 release. Their stability was found tobe metal-dependent. The thermal decomposition pathways were correlated with the existing structural data about the compounds.