How to zip two lists of lists

I have two lists of lists that have equivalent numbers of items. The two lists look like this:

L1 = [[1, 2], [3, 4], [5, 6]]

L2 =[[a, b], [c, d], [e, f]]

I am looking to create one list that looks like this:

Lmerge = [[1, 2, a, b], [3, 4, c, d], [5, 6, e, f]]

I was attempting to use zip() something like this:

for list1, list2 in zip(*L1, *L2):
    Lmerge = [list1, list2]

What is the best way to combine two lists of lists? Thanks in advance.