The SE part of the Carpathian-Pannonian region records the cessation of convergence between the European platform/Moesia and the Tisza-Dacia microplate. Pliocene-Quaternary magmatic activity in this area, in close proximity to the ‘Vrancea zone’, changed from normal calc-alkaline type to much more diverse magma compositions at approximately 3 Ma, suggesting a significant change in geodynamic processes. We review the tectonic setting, timing, petrology and geochemistry of the post-collisional volcanism to constrain the role of orogenic processes such as subduction and collision on melt production and migration. The calc-alkaline volcanism (5.3-3.9 Ma) marks the end of normal subduction-related magmatism along the post-collisional Călimani-Gurghiu-Harghita volcanic chain in front of the European convergent plate margin. In South Harghita magma compositions changed at 3 Ma to adakitelike calc-alkaline and continued until recent times (< 0.03 Ma) interrupted at 1.6-1.2 Ma by generation of Na and K alkalic magmas, signifying changes in the source and melting mechanism. We attribute the changes in magma composition in front of the Moesian platform to two main geodynamic events: (1) slab-pull and steepening with opening of a tear window (adakite-like calc-alkaline magmas) and (2) renewed contraction associated with deep mantle processes such as slab steepening during post-collisional times (Na and K alkalic magmas). Contemporaneous post-collisional volcanism at the eastern edge of the Pannonian Basin at 2.6-1.3 Ma was dominated by Na alkalic and ultrapotassic magmas, suggesting a close relationship with thermal asthenospheric doming and strain partitioning related to the Adriatic indentation. Similar timing, magma chamber processes and volume for K-alkalic (shoshonitic) magmas in the South Apuseni Mountains (1.6 Ma) and South Harghita area at a distance of ca. 200 km imply a regional connection with inversion tectonics.