The Galway welterweight, competing at middleweight, was cruelly edged out at the quarter-final stage, missing out on a bronze medal following a close split decision loss.
The World and European Youth bronze medalist, from the Olympic club, was beaten by Georgian Giorgi Kharabadze, a European Junior gold and European Youth bronze medalist, after three close rounds in Targu Jiu.
A cagey opener saw southpaw Dossen, the much longer fighter staying outside as Kharabadze lunged in, making it messy.
The Eastern European had a good start to round two, landing some big shots, but Dossen regained control in the second half and began to time and counter effectively.
Dossen continued this in the final round, dictating the pace, before a strong finish from the Georgian which secured him the split-decision win and leaving the Irish fighter heartroken.
Louth lightweight Amy Broadhurst and Roscommon middleweight, Ireland’s last remaining fighters, are both in semi-final action this evening looking to upgrade their bronze medals to silvers when they face Belinda Limuka (France) and Carlotta Paoletti (Italy) respectively.
51kg Niamh Earley (Ireland) lost to Aikaterini Koutsogeorgo (Greece) 0-5
57kg Shauna Blaney (Ireland) lost to Nedkova Ivanova (Bulgaria) 1-4
52kg Conor Quinn (Ireland) lost to Maksim Stakheev (Russia) 1-4
91kg Kevin Sheehy (Ireland) lost to Felix Kuhne (Germany) 0-5
75kg Gabriel Dossen (Ireland) beat Hambardum Hakobya (Armenia) 4-1
56kg Jordan Moore (Ireland) lost to Eusebi Jitaru (Romania) 0-5
48kg Shannon Sweeney (Ireland) lost to Mari-Emi Todorova (Bulgaria) 0-5
60kg Amy Broadhurst (Ireland) beat Esra Yildiz (Turkey) 5-0
75kg Gabriel Dossen (Ireland) lost to Giorge Kharabadze (Georgia)
60kg Amy Broadhurst (Ireland) V Belinda Limuka (France)
75kg Aoife O’Rourke (Ireland) v Carlotta Paoletti (Italy)