Magnesium oxalate can by synthesized by combining a magnesium salt or ion with an oxalate.
: Mg + CO → MgCO
A specific example of a synthesis would be mixing Mg(NO) and KOH and then adding that solution to dimethyl oxalate, (COOCH).
When heated, magnesium oxalate will decompose. First, the dihydrate will decompose at 150 °C into the anhydrous form.
: MgCO•2HO → MgCO + 2 HO
With additional heating the anhydrous form will decompose further into magnesium oxide and carbon oxides between 420 °C and 620 °C. First, carbon monoxide and magnesium carbonate form.  The carbon monoxide then oxidizes to carbon dioxide, and the magnesium carbonate decomposes further to magnesium oxide and carbon dioxide.
: MgCO → MgCO + CO
: CO + 1/2 O → CO
: MgCO → MgO + CO
Magnesium oxalate dihydrate has also been used in the synthesis of nano sized particles of magnesium oxide, which have larger surface are to volume ratio than conventionally synthesized particles and are optimal for various applications, such as in catalysis. By using a sol-gel synthesis, which involves combining a magnesium salt, in this case magnesium oxalate, with a gelating agent, nano sized particles of magnesium oxide can be produced.