What answer are you expecting?
L is 2 x 4 with each element 1 x 1, so most likely L should be considered to be like a 2 x 4 matrix.
D is 2 x 2 with each element 1 x 2. One of the ways to view that would be as a 2 x 4 matrix.
But if one views this as a (2 x 4) * (2 x 4) then the "*" operator must fail because the inner dimensions do not agree.
I am going to speculate that you asked the wrong question and that what you want is L .* D
cell2mat(L) .* cell2mat(D)