Reducing light pollution and promoting sustainable lighting practices require new tools that integrate environmental, social, and technical considerations in design processes. Urban Digital Twins are emerging as powerful instruments for this purpose, enabling integrated evaluation of lighting impacts on both people and ecosystems. This paper presents an exploratory evaluation of NorDark-DT, a recently developed urban digital twin designed to support the sustainable planning of lighting infrastructure in green urban areas. This exploratory assessment was conducted with master’s students engaged in lighting design practices. Participants performed two task-oriented exercises of planning and comparing lighting configurations after-dark for a site in Uppsala, Sweden. Results show that NorDark-DT effectively facilitates the exploration of alternative lighting solutions within realistic green urban area contexts and encourages reflection on issues such as light pollution, biodiversity, and ecological preservation. Nevertheless, further improvements are required to enhance the user interface, expand analytical capabilities, strengthen integration with professional lighting software, and optimize performance for varying hardware setups. Beyond professional practice, the tool also proved valuable for educational purposes by promoting interdisciplinary collaboration and broadening students’ understanding of sustainability in lighting design. Overall, this study provides an initial step in a usability assessment of NorDark-DT, confirming its potential to support environmentally responsible, socially aware, and well-informed lighting interventions.