The synthesis, characterization and TG-DSC study of the compounds CdX(2)(.)ncaff, for which X: Cl, Br and 1; n = I and 2 and caff: caffeine is reported. It is verified that caffeine is coordinated through more than one coordination site, despite the fact that the nitrogen of the imidazole ring is the main coordination site. The following thermal stability trend is observed: Cl > Br > I and monoadducts are more stable than bisadducts. The thermal degradation (td) enthalpies have the values (kJ mol(-1)): 58.2 and 71.5; 74.9 and 91.4; 31.1 and 47.5 for Cl, Br and I mono and bisadducts, respectively. (C) 2003 Elsevier Science B.V. All rights reserved.