Use zip()
to pair up the lists and produce tuples from that:
list3 = [(l1[0], l1[1], l2) for l1, l2 in zip(list1, list2)]
Demo:
>>> list1 = [(2345,7465), (3254,9579)]
>>> list2 = [{'type': '62', 'length': 0.15, 'lanes': 1, 'modes': 'cwt'}, {'type': '62', 'length': 0.16, 'lanes': 1, 'modes': 'cwt'}]
>>> [(l1[0], l1[1], l2) for l1, l2 in zip(list1, list2)]
[(2345, 7465, {'lanes': 1, 'length': 0.15, 'type': '62', 'modes': 'cwt'}), (3254, 9579, {'lanes': 1, 'length': 0.16, 'type': '62', 'modes': 'cwt'})]