BiMol-Diff: A Unified Diffusion Framework for Molecular Generation and Captioning

Aditya Hemant Shahane, Anuj Kumar Sirohi, Devansh Arora, Nitin Kumar, Prathosh AP, Sandeep Kumar


Abstract
Bridging molecular structures and natural language is essential for controllable design. Autoregressive models struggle with long-range dependencies, while standard diffusion processes apply uniform corruption across positions, which can distort structurally informative tokens. We present BiMol-Diff, a unified diffusion framework for the paired tasks of text-conditioned molecule generation and molecule captioning. Our key component is a token-aware noise schedule that assigns position-dependent corruption based on token recovery difficulty, preserving harder-to-recover substructures during the forward process. On ChEBI-20 and M3-20M, BiMol-Diff improves molecule reconstruction with a 15.4% relative gain in Exact Match and achieves strong captioning results, attaining best BLEU and BERTScore among compared baselines. These results indicate token-aware noising improves fidelity in molecular structure-language modeling
Anthology ID:
2026.acl-long.1059
Volume:
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Maria Liakata, Viviane P. Moreira, Jiajun Zhang, David Jurgens
Venue:
ACL
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Publisher:
Association for Computational Linguistics
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Pages:
23104–23117
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URL:
https://preview.aclanthology.org/ingest-acl/2026.acl-long.1059/
DOI:
Bibkey:
Cite (ACL):
Aditya Hemant Shahane, Anuj Kumar Sirohi, Devansh Arora, Nitin Kumar, Prathosh AP, and Sandeep Kumar. 2026. BiMol-Diff: A Unified Diffusion Framework for Molecular Generation and Captioning. In Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers), pages 23104–23117, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
BiMol-Diff: A Unified Diffusion Framework for Molecular Generation and Captioning (Shahane et al., ACL 2026)
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https://preview.aclanthology.org/ingest-acl/2026.acl-long.1059.pdf
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