Jason Byrne bagged a brace as Bohs became the first team into the last four of the FAI Ford Cup.
Leading 2-0 at half time at the Carlisle Grounds in Bray, the Premier Division leaders recorded their tenth win on the spin as they eased past non-League Wayside.
The Gypsies went close as early as the sixth minute as Gary Deegan's slide rule pass released John Paul Kelly. But he was thwarted by Celtic goalkeeper Robbie O'Dowd who made a parry save and recovered to gather the loose ball.
The Gypsies went ahead in the 13th minute.
Owen Heary skipped down the right flank and sent in a by-line cross which took a cruel deflection, evading O'Dowd as Kelly pounced with a ten-yard flick to the net.
That led was doubled six minutes later as Irish U-23 cap Kelly turned provider.
His measured ball over the top down the left channel released Byrne who instinctively guided a precise lob over the on-rushing custodian from 15 yards.
Pat Fenlon's men went close to adding to their tally with three chances on the stroke of half time.
First O'Dowd denied Kelly after good work by Brendan McGill and Gary Deegan.
Then Neal Fenn slipped in the breaking Mark Rossiter who shot across the face of goal.
The midfielder had another opportunity to score, but the busy O'Dowd made a point blank save off Rossiter's driven half-volley.
Any hope of a comeback by the Leinster Senior League outfit was snuffed out within seven minutes of the restart.
Heary sent a flighted free from the right wing into the box. Jason McGuinness rose with O'Dowd and the towering central defender glanced a close range header to the net.
Within three minutes, Kelly was brought down by Alan Sharkey and Byrne blasted in the resulting spot kick.
But Wayside got on the scoresheet on the hour mark, as captain Wayne Callaghan whipped in a free-kick which his brother Ian powered past Brian Murphy from ten-yards as the net-minder conceded his first goal in the competition.
However, this only served to spur Bohs on. Heary burst on a 77th minute right flank throw to set up Fenn who fired past low O'Dowd from 12 yards.
Substitute Glen Crowe completed the rout in the 81st minute. Deegan squared to the forward whose shot from the edge of the area deflected off the unfortunate Paddy Byrne and wrong-footed O'Dowd.
Wayside Celtic: O'Dowd; O'Reilly (Paddy Byrne 58 mins), Wayne Callaghan, Sharkey, Hynes; Pratt, Hyland (Brien 68 mins), Simpson, Lucey (Gill 58 mins), Hanlon, Ian Callaghan.
Bohemians: Murphy; Heary, Burns, McGuinness, Powell; McGill, Deegan (Cronin 86 mins), Rossiter (O'Donnell 53 mins), Kelly; Fenn, Jason Byrne (Crowe 77 mins).
Referee: Ian Stokes (Dublin).
