This dataset consists of files relevant to the research paper, "Exploring Creativity in Human-Human-LLM Collaborative Software Design" accepted by the International Conference on Evaluation and Assessment in Software Engineering (EASE) 2026. This lab-based study consisted of 18 pairs of software professionals completing a design task. They were free to use any design methodology and tools and were given optional access to a chat-based tool that leveraged an LLM. The accompanying paper provides details of the research method followed by the study and should be read in conjunction with this data. The research question explored in the study was: "How, and where, does creativity appear naturally when designing with an LLM?" The dataset is provided to share additional data relevant to the study findings and to aid other researchers interested in repeating or running a similar study.