When Vision Meets Texts in Listwise Reranking

Recent advancements in information retrieval have highlighted the potential of integrating visual and textual information, yet effective reranking for image-text documents remains challenging due to the modality gap and scarcity of aligned datasets. Meanwhile, existing approaches often rely on large models (7B to 32B parameters) with reasoning-based distillation, incurring unnecessary computational overhead while primarily focusing on textual modalities. In this paper, we propose Rank-Nexus, a multimodal image-text document reranker that performs listwise qualitative reranking on retrieved lists incorporating both images and texts. To bridge the modality gap, we introduce a progressive cross-modal training strategy. We first train modalities separately: leveraging abundant text reranking data, we distill knowledge into the text branch. For images, where data is scarce, we construct distilled pairs from multimodal large language model (MLLM) captions on image retrieval benchmarks. Subsequently, we distill a joint image-text reranking dataset. Rank-Nexus achieves outstanding performance on text reranking benchmarks (TREC, BEIR) and the challenging image reranking benchmark (INQUIRE, MMDocIR), using only a lightweight 2B pretrained visual-language model. This efficient design ensures strong generalization across diverse multimodal scenarios without excessive parameters or reasoning overhead.