Evaluating Multi-Hop Reasoning in Large Language Models: A Chemistry-Centric Benchmark

Mohammad Khodadad, Ali Shiraee Kasmaee, Mahdi Astaraki, Nicholas Sherck, Hamidreza Mahyar, Soheila Samiee


Abstract
We introduce ChemComp, the first chemistry-focused benchmark for evaluating compositional multi-hop reasoning in large language models (LLMs). Our automated pipeline constructs benchmarks from proprietary or public data by integrating generative reasoning models, chemical named-entity recognition, and external knowledge bases to build knowledge graphs. Applied to recent chemistry literature, this approach minimizes overlap with LLM pretraining data. The resulting dataset comprises 1,188 multi-hop questions, refined through domain-expert feedback and robust evaluation protocols.Using ChemComp, we systematically compare LLM performance with and without retrieval augmentation, including an idealized gold-context scenario. Our results show that even state-of-the-art models struggle with compositional reasoning: retrieval significantly improves accuracy, yet reasoning errors persist even under perfect retrieval. These findings highlight the limitations of current LLMs and the critical role of retrieval-augmented methods in scientific reasoning. Furthermore, our pipeline is generalizable with fine-tuning, enabling the creation of challenging multi-hop reasoning benchmarks across domains and proprietary datasets.
Anthology ID:
2026.findings-eacl.322
Volume:
Findings of the Association for Computational Linguistics: EACL 2026
Month:
March
Year:
2026
Address:
Rabat, Morocco
Editors:
Vera Demberg, Kentaro Inui, Lluís Marquez
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Findings
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Publisher:
Association for Computational Linguistics
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Pages:
6117–6143
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https://preview.aclanthology.org/ingest-eacl/2026.findings-eacl.322/
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Cite (ACL):
Mohammad Khodadad, Ali Shiraee Kasmaee, Mahdi Astaraki, Nicholas Sherck, Hamidreza Mahyar, and Soheila Samiee. 2026. Evaluating Multi-Hop Reasoning in Large Language Models: A Chemistry-Centric Benchmark. In Findings of the Association for Computational Linguistics: EACL 2026, pages 6117–6143, Rabat, Morocco. Association for Computational Linguistics.
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Evaluating Multi-Hop Reasoning in Large Language Models: A Chemistry-Centric Benchmark (Khodadad et al., Findings 2026)
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