Question: why zncl2 is soluble in organic solvent?
Answer: No matter, the main reason is the MgCl2 is much more ionic and this is assessed by the difference in electronegativity (EN) between Mg and Cl vs between Zn and Cl. The small the difference (in an absolute difference) the more covalent the bonds will be and therefore more soluble in organic (non-polar) solvents.