The evolution of open science in cheminformatics: a journey from closed systems to collaborative innovation.

Cheminformatics has significantly transformed over the past four decades, evolving from a field dominated by proprietary systems to one increasingly embracing open science principles. In its early years, cheminformatics was characterised by commercial software and restricted data access, limiting collaboration and reproducibility. The advent of open-source software in the late 1990s and early 2000s, including tools such as the Chemistry Development Kit (CDK) and RDKit, played a crucial role in democratising computational chemistry. Open data initiatives, such as PubChem and NMRShiftDB, further enhanced accessibility by providing freely available chemical information, fostering transparency and interoperability and introducing key standards, such as the International Chemical Identifier (InChI), revolutionised data integration and retrieval across diverse platforms. Community-driven efforts, including the Blue Obelisk movement and Open Notebook Science, have promoted open methodologies and collaborative research. More recently, national data infrastructure projects like NFDI4Chem have aimed to standardise research data management in cheminformatics, ensuring the long-term sustainability of open science practices. The increasing adoption of the FAIR (Findable, Accessible, Interoperable, Reusable) principles has further reinforced data sharing and reuse in computational chemistry. Challenges remain, particularly in overcoming resistance to data sharing and ensuring sustainable funding for open projects. However, the trajectory of cheminformatics demonstrates that embracing openness enhances scientific integrity and accelerates discovery and innovation.