The synthesis of the new germylated and phosphorylated heterocycles 2-anisyl-4,4-dimethyl-2-thio-1,3,2,4-dithiaphos-phagermetane, [Formula: see text] (1), and 5-anisyl-2,2,3,3-tetramethyl-5-thio-1,4,5,2,3-dithiaphosphadigermolane, [Formula: see text] (2), are described. The decomposition of 1 with formation of (Me2GeS)3 and (AnPS2)n is observed at room temperature. At 200 °C 2 undergoes thermal fragmentation leading to (Me2GeS)3 and (AnPS)n. These results are explained by two mechanisms of decomposition involving formation of transient species [Me2Ge = S] and [AnPS2] or [AnPS], respectively. Exchange reactions between 2 and various metal (MIVB) chlorides are described. With Me2SiCl2 the reaction leads to silathione [Me2Si = S], probably via transient dithiaphosphasiletane.