Key points
- Core problem: Text-only LLMs used in AI-driven drug discovery hallucinate molecular descriptors such as polar surface area and lipophilicity (logP) by extrapolating from journal-text context rather than computing them, producing plausible but unreliable pharmacological reasoning.
- Proposed architecture: Bolek is a 4B-parameter multimodal model built on Qwen3 that injects deterministic molecular features into the language model.
- Grounding mechanism: Morgan fingerprints, the chemistry community's standard encoding of molecular structure as numeric vectors, are translated into embeddings and concatenated with text tokens via a projector:
- Training rule: Before producing any pharmacological conclusion, the model must explicitly recite the underlying structural fingerprint values, making numeric grounding a hard constraint rather than a learned afterthought.
- Benchmark results: On 15 real-world drug-property prediction tasks, Bolek outperformed the 9B chemistry-tuned TxGemma despite being less than half its size.
- Grounding frequency: Bolek cited real underlying structural values 10 to 100 times more often than text-only baselines.
- Correlation with professional tools: Bolek's predictions correlated at r = 0.91 with values produced by established cheminformatics software.
- Strategic argument: Scaling text corpora and context length cannot fix scientific hallucination. Physical measurements, not rhetorical fluency, are the foundation of valid scientific inference, and small grounded models can outperform larger text-only ones at a fraction of the cost.
- Title: Bolek: A Multimodal Language Model for Molecular Reasoning
- Authors: Frederic Grabowski, Tomasz Jetka, et al.
- Affiliations: Ingenix.ai; Warsaw University of Technology
- Date: 2026-05-04
- Categories: cs.LG, cs.AI
$$\text{Embedding} = \text{Projector}(\text{Morgan\_Fingerprint}) \oplus \text{Text\_Tokens}$$