If L1 and L2 are list objects containing keys and respective values, following methods can be used to construct dictionary object.
Zip two lists and convert to dictionary using dict() function
>>> L1 = ['a','b','c','d']
>>> L2 = [1,2,3,4]
>>> d = dict(zip(L1,L2))
>>> d
{'a': 1, 'b': 2, 'c': 3, 'd': 4}
Using dictionary comprehension syntax
>>> L1 = ['a','b','c','d']
>>> L2 = [1,2,3,4]
>>> d = {k:v for k,v in zip(L1,L2)}
>>> d
{'a': 1, 'b': 2, 'c': 3, 'd': 4}