Organic solar cells are particularly attractive for their very low fabrication cost, and lack of use of critical raw materials. While this has to date been hobbled by low efficiency, recent achievements demonstrate organic single junction technology at 20% efficiency approaching economically viable performance. We survey the reasons for these recent high efficiency organic solar cell achievements. They include bulk heterojunction (BHJ) concepts, composed of electron donor materials, most often a semiconductor polymer and electron accepting materials, most often a small molecule, and the novel non-fullerene acceptor materials. The range of commercially available donor and acceptor materials available offers a large design flexibility for low or high band gap devices. A natural development for this emerging thin film technology reaching competitive efficiencies is its integration in tandem solar cells. In the context of the breakthroughs in organic solar cell efficiency, this work presents first results of the ORGANIST project (2023-2027) supported by the French Research National Agency. The presentation of organic materials for top cells and their efficient integration on a high efficiency silicon IBC cell is discussed with a critical focus on the interface between top organic solar cell and bottom silicon IBC cell. We present preliminary theoretical results evaluating the performance of 3T devices being developed in ORGANIST and based on identified prototype materials for the organic cell, strategies for efficient optical and electrical connection between the two subcells, aiming for low cost three terminal organic / silicon tandems with high efficiencies above the Shockley-Queisser single bandgap limit for Silicon.