Nowadays, the adoption of a single and unified electricity market [1] is one of the main challenges faced by Europe. Although the Western and Northern regions of Europe have been working for several years towards reaching such objective, the South-Eastern region of Europe has not followed the same roadmap and it not as advanced in this field as Western Europe. TRINITY will address this challenge in order to improve the current situation and facilitate the interconnection of South-Eastern electricity markets - among them and also within the current Multi Regional Coupling area (MRC). TRINITY will develop a set of solutions to enhance cooperation among the transmission system operators of SEE in order to support the integration of the electricity markets in the region, whilst promoting higher penetration of clean energies. This strategic goal will be driven by end-users (8 TSOs, 4 NEMOS and 1 RCC) and will be achieved through the deployment in the region of four independent, but complementary, products: T-Market Coupling Framework; T-Sentinel Toolset; T-RES Control Center and T-Coordination Platform.