Social Sciences and Humanities (SSH) provide essential knowledge to society, informing our shared cultural, economical and ethical decisions. However, SSH knowledge remains largely disconnected and poorly available, impeding its full potential in research and societal applications. The GRAPHIA project aims to build the first comprehensive SSH Knowledge Graph (KG) that integrates currently disconnected data into a single entry point, leveraging existing infrastructure and data resources. GRAPHIA aspires to significantly improve SSH data visualisation and analysis capacities, pioneer advanced AI solutions tailored for SSH and develop re-usable, cutting-edge digital tools. GRAPHIA addresses the unique opportunities posed by the qualitative, diverse and context-rich data typical of SSH research where existing solutions fall short. GRAPHIA's innovative approach, centered around the KG, provides an expansive representation of SSH knowledge, while leveraging AI for its enrichment, access and deeper analysis, including an LLM4SSH. GRAPHIA aims to empower researchers to uncover patterns and insights from unstructured data, illuminating social phenomena and cultural trends with unprecedented clarity. A key component of GRAPHIA is the SSH Citation Index, an innovative framework for citation data extraction and enrichment across all SSH disciplines that dramatically speeds up access and understanding of previous literature on any topic. GRAPHIA transcends traditional research approaches by integrating industry partners into a cohesive partnership, which is pivotal to amplify the project's impact, drive forward innovations that are not only academically significant but also commercially viable, provide access to new markets and technologies and foster an environment of co-innovation. GRAPHIA is committed to open science and increasing EU Research Infrastructures capabilities, enhancing global competitiveness, while facilitating broad and long-lasting impact of project results.