Recent advancements in Large Language Models (LLMs) have showcased their proficiency in answering natural language queries. However, their effectiveness is hindered by limited domain-specific knowledge, raising concerns about the reliability of their responses. We introduce a hybrid system that augments LLMs with domain-specific knowledge graphs (KGs), thereby aiming to enhance factual correctness using a KG-based retrieval approach. We focus on a medical KG to demonstrate our methodology, which includes (1) pre-processing, (2) Cypher query generation, (3) Cypher query processing, (4) KG retrieval, and (5) LLM-enhanced response generation. We evaluate our system on a curated dataset of 69 samples, achieving a precision of 78% in retrieving correct KG nodes. Our findings indicate that the hybrid system surpasses a standalone LLM in accuracy and completeness, as verified by an LLM-as-a-Judge evaluation method. This positions the system as a promising tool for applications that demand factual correctness and completeness, such as target identification — a critical process in pinpointing biological entities for disease treatment or crop enhancement. Moreover, its intuitive search interface and ability to provide accurate responses within seconds make it well-suited for time-sensitive, precision-focused research contexts. We publish the source code together with the dataset and the prompt templates used.

Vision-Language Models (VLMs) have achieved impressive progress across diverse multimodal tasks, yet their ability to interpret structured diagrams, such as circuit schematics, molecular structures, musical notation, business process flow charts or class diagrams, which are central to scientific and engineering communication, remains underexplored. We introduce STRUDEL (STRUctured Diagram EvaLuation), a benchmark for evaluating VLMs on structured diagram understanding across 8 domains and 20 image categories. STRUDEL leverages Large-Language Models (LLMs) to synthesize code in domain-specific formal representation languages (FRLs) (e.g. circuit netlists, SMILES, ABC-Notation, BPMN or PlantUML), which are rendered into valid diagrams and paired with generated tasks, functional descriptions, and captions. A multi-stage pipeline filters invalid, cluttered, or redundant samples and employs LLM-as-a-judge scoring to ensure correctness. Through targeted experiments, we evaluate the ability of LLMs to generate valid code in distinct FRLs, demonstrating their capability to successfully perform this task. The resulting benchmark comprises diverse task types covering identification, quantification, structural analysis, image-text association, and image-to-code translation. Evaluating 35 VLMs using STRUDEL reveals that models excel at association tasks, demonstrating strong visual-textual alignment, yet struggle with quantification and identification, where precise structural understanding is required. Performance varies markedly in image-to-code translation, reflecting significant differences in how models connect visual inputs to formal representations. Overall, STRUDEL establishes a scalable foundation for assessing and advancing VLMs torward deeper and more systematic understanding of structured visual information across domains.