Scotland gained a consolation win in the third and final game of the series as they won by 56 runs at Comber.
Finlay Carter's 62 helped them to 254, with runs too for Rory Grant (34), James Woodhouse (24), and Ollie Jones (22).
Tom Ford (3-39) was the pick of the Irish bowling unit.
The chase was a tense one as Seb Dijkstra (36), Rob O'Brien (34), Dan Murray (29) and James West (24) all got starts but couldn't kick on.
At 187 for 5 the game was evenly poised before the Irish collapsed, losing their last five wickets for 11 runs to be 198 all out.
Manu Saraswat of Aberdeenshire was again the pick of the attack, taking three wickets to bring his tally to seven across the three matches, while James West was the series leading run scorer with 214.
In Wednesday's second game, A 124 run partnership for the seventh wicket between Finlay Carter and Ollie Jones carried the Scots to an impressive 268 in their 50 overs.
Ethan Marshall with three wickets for the Irish who paid the price for dropped catches.
Scotland would also rue their dropped catches as James West took full advantage of his good fortune to post a match winning unbeaten century. Ireland winning with more than four overs to spare.