list1 Inner[{#2,#1}&,list2,{0,1}, #2&]
In the example given by the OP (but not in the general case of the question title), all the second elements in list2
are also identical, and Dot may be used to 'multiply a matrix column by a factor', and get the same result:
list1.{{1,0},{0,list2[[1,2]]}}
And:
(list1 Inner[{#2,#1}&,list2,{0,1}, #2&])===(list1.{{1,0},{0,list2[[1,2]]}})
True
Yet another method is the following:
list1 ArrayFlatten[{{1, List/@list2[[All,2]]}}]
For this use of ArrayFlatten
see this old SO answer by Janus
Original Answer
list1 Inner[{1,#1}&,list2,{1,0}, #2&]