Organizations: University of Science and Technology of China · Shanghai Artificial Intelligence Laboratory · Fudan University · National University of Singapore · The University of Hong Kong · Nanyang Technological University · Northwestern Polytechnical University · Tongji University
Multimodal Large Language Models (MLLMs) excel in general domains but struggle with complex, real-world science. We posit that polymer science, an interdisciplinary field spanning chemistry, physics, biology, and engineering, is an ideal high-stakes testbed due to its diverse multimodal data. Yet, existing benchmarks related to polymer science largely overlook real-world workflows, limiting their practical utility and failing to systematically evaluate MLLMs across the full, practice-grounded lifecycle of experimentation. We introduce PolyReal, a novel multimodal benchmark grounded in real-world scientific practices to evaluate MLLMs on the full lifecycle of polymer experimentation. It covers five critical capabilities: (1) foundational knowledge application; (2) lab safety analysis; (3) experiment mechanism reasoning; (4) raw data extraction; and (5) performance & application exploration. Our evaluation of leading MLLMs on PolyReal reveals a capability imbalance. While models perform well on knowledge-intensive reasoning (e.g., Experiment Mechanism Reasoning), they drop sharply on practice-based tasks (e.g., Lab Safety Analysis and Raw Data Extraction). This exposes a severe gap between abstract scientific knowledge and its practical, context-dependent application, showing that these real-world tasks remain challenging for MLLMs. Thus, PolyReal helps address this evaluation gap and provides a practical benchmark for assessing AI systems in real-world scientific workflows.
Figures & tables
Figure 1: Overview of the PolyReal benchmark and its five-stage workflow.
Benchmark
Domain
Size
Modality
Workflow
Type
MacBench
Organic Chem.
80
Multi
×
MCQ, Num.
SFE
General Chem.
285
Multi
×
MCQ, EM, OQ
MatSciBench
Polymer Chem.
12
Multi
×
Num., OQ
MSQA
Polymer Chem.
257
Single
×
T/F, OQ
MatCha
Polymer Chem.
98
Multi
×
MCQ
PolyReal
Polymer Chem.
545
Multi
✓
OQ, Rank
Table 1: Comparison with representative chemistry and materials benchmarks. MCQ: multiple-choice; Num.: numeric; EM: exact match; OQ: open question; T/F: true/false; Rank: ranking.
Figure 2: Overview of the PolyReal benchmark’s composition, comprising 545 high-quality question-answer pairs: (a) Distribution of questions across the five core workflow modules covering the full research lifecycle; and (b) Comprehensive topic coverage, detailing the distribution across eight key sub-fields of polymer science.
Figure 3: Comparison of model performance across PolyReal , evaluated by F1 score.
Metric-Specific Score Correlation
Spearman’s ρ
Recall ( R ) Scores (Completeness)
0.95
Precision ( P ) Scores (Correctness)
0.91
F1-Scores
0.94 *
Table 2: Spearman’s ( ρ ) correlation between Human Expert and Automated Evaluator scores for P, R, and F1 metrics. *
Figure 4: Qualitative examples of MLLM failure modes: (Case 1) misapplying known principles and (Case 2) misinterpreting raw spectral data.
FKA
LSA
EMR
RDA
PAE
Overall
Model
P
R
F1
P
R
F1
P
R
F1
P
R
F1
P
R
F1
P
R
F1
Closed-source Models
O3
0.608
0.775
0.641
0.366
0.541
0.412
0.565
0.745
0.611
0.424
0.553
0.422
0.579
0.733
0.609
0.567
0.733
0.601
GPT-5
0.544
0.799
0.594
0.317
0.563
0.373
0.543
0.801
0.608
0.418
0.523
0.426
0.581
0.742
0.623
0.529
0.760
0.578
Claude-Sonnet-4.5-Thinking
0.519
0.752
0.580
0.282
0.411
0.317
0.539
0.700
0.578
0.354
0.489
0.356
0.526
0.663
0.539
0.503
0.692
0.546
Gemini-2.5-Pro
0.505
0.780
0.570
0.338
0.479
0.369
0.480
0.726
0.535
0.389
0.592
0.408
0.521
0.677
0.555
0.483
0.726
0.536
Table 3: Performance comparison of different models on various benchmarks. P , R , and F1 represent Precision, Recall, and F1-score, respectively. LSA : Lab Safety Analysis, FKA : Foundational Knowledge Application, EMR : Experiment Mechanism Reasoning, RDA : Raw Data Extraction and Analysis, PAE : Performance & Application Exploration. The best results are in bold and the second best are underlined .
Figure 5: Comparison of model performance across the eight key polymer science sub-fields in PolyReal , evaluated by F1 score.
Method
Precision ( P )
Recall ( R )
F1-Score ( F1 )
Gemini-2.5-pro (w Image)
0.41
0.79
0.51
w/o Image (Text-Only)
0.36
0.71
0.45
o3 (w Image)
0.56
0.74
0.60
w/o Image (Text-Only)
0.53
0.70
0.56
Table 4: Ablation Study on the Importance of Modality. Performance comparison between the full multimodal input (”With Image”) and the ”Text-Only” (w/o Image) version.
Method
Precision ( P )
Recall ( R )
F1-Score ( F1 )
GPT-4o (Closed-Book)
0.58
0.30
0.35
w/ Search Tool
0.56
0.38
0.41
GPT-4o-mini (Closed-Book)
0.50
0.25
0.29
w/ Search Tool
0.48
0.32
0.34
Table 5: Ablation Study on the Role of External Knowledge.
Hard
Medium
Easy
Overall
Model
P
R
F1
P
R
F1
P
R
F1
P
R
F1
Closed-source Models
O3
0.458
0.503
0.430
0.544
0.672
0.561
0.621
0.853
0.686
0.567
0.733
0.601
GPT-5
0.432
0.546
0.419
0.483
0.692
0.520
0.590
0.876
0.669
0.529
0.760
0.578
Claude-Sonnet-4.5-Thinking
0.392
0.432
0.365
0.480
0.638
0.513
0.559
0.820
0.632
0.503
0.692
0.546
Gemini-2.5-Pro
0.416
0.455
0.378
0.465
0.679
0.512
0.519
0.853
0.608
0.483
0.726
0.536
Table 6: Performance comparison of different models across three difficulty levels ( Hard , Medium , Easy ) and the Overall weighted average. P , R , and F1 represent Precision, Recall, and F1-score, respectively. The best results are in bold and the second best are underlined .
Figure 6: Performance comparison across difficulty levels. F1-scores for representative models are reported across Easy, Medium, and Hard subsets. A consistent performance degradation is observed as task complexity increases, with the ”Hard” subset effectively differentiating robust state-of-the-art models (e.g., o3) from lightweight counterparts (e.g., GPT-4o-mini) which experience steeper declines.
Figure 7: The standardized system prompt used for zero-shot inference across all MLLMs, enforcing a structured Chain-of-Thought reasoning process.
Figure 8: The full prompt template for the Precision Evaluator. We explicitly categorize distinct types of noise (highlighted in red ) to rigorously penalize hallucinations and ensuring the Precision metric reflects true information density.
Figure 9: Full prompt for the Precision Evaluator. The explicit categorization of False Positives (highlighted in red) ensures that verbose or hallucinatory content is accurately penalized.
Figure 10: Qualitative analysis of a failure case. Specific chemical substances are highlighted in blue, and identified safety hazards are highlighted in red.
Model
Precision (Avg.)
Recall (Avg.)
F1 (Avg.)
LLaVA-v1.6-Vicuna-13B
0.110
0.058
0.053
Qwen3-VL-2B-Thinking
0.213
0.196
0.166
InternVL3_5-8B
0.415
0.366
0.337
Qwen3-VL-8B-Instruct
0.543
0.345
0.366
Qwen3-VL-8B-Thinking
0.442
0.442
0.395
Table 7: Performance of additional small models on PolyReal.
State Key Laboratory for Multimedia Information Processing, School of Computer Science, PKU-Anker LLM Lab, Peking University · IDEA · Zhongguancun Academy +5