Thermolysis of bis(trimethylstannyl)diazomethane (1) or bis(tributylstannyl)diazomethane (2) affords the corresponding bis(stannyl)carbodiimides 3-4. Bis(trimethylstannyl)carbodiimide (3) is also obtained at room temperature by palladium-catalyzed isomerization of diazo derivative 1 and is a powerful precursor of elaborated carbodiimides.