Ex-Bray striker Paul Keegan scored a stunning opening goal as Bohs cruised into the last four of the FAI Cup.
Keegan volleyed home Bobby Ryan's free-kick on 13 minutes and Bohs were never in any real trouble after that.
Glen Crowe added the second on 41 minutes when Paul McNally's header set him up from Ryan's corner.
McNally then hit a stunning third goal with a left-foot volley on 66 minutes.
Substitute Gary O'Neill made it 4-0 two minutes from time to complete an easy win.