According to the United Nations declarations in 2019, cities, as humanity’s primary living habitat, will accommodate 68% of the world’s population by 2050. The more people settle in urban centres, the more severe the impacts are on ecosystems and the climate. Due to rapid urbanisation, the number of unused and under-managed urban spaces or “Urban voids” is rising. However, regenerative approaches can turn urban voids into assets to combat climate change and environmental issues. The regenerative design promotes ecological systems to regrow by allowing every urban component, like houses, workplaces, and neighbourhoods, to flourish ecologically. This research starts with reviewing related terms for urban voids beside a fundamental approach towards utilising them, “Interim re-use.” With these in hand, the research’s methodology mapped 577 urban voids in its “Balat and Fener” case study, two juxtaposing historical districts in Istanbul, Turkey. The study goes on to classify the mapped urban voids into six distinctive types. The classification of urban voids is done using a decision tree model with five features that are assigned binary values. The features are as follows: “Ownership,” “Debris,” “Economic activity,” “Seal,” and “Leisure facilities.” The next phase evaluates each parcel based on ecological criteria; each void is rated through a Likert scale in terms of “Vegetation,” “Permeability,” “Ruggedness,” and “Enclosure,” and thence, receives an ecological identity. After each parcel is classified and assigned its ecological identity, a two-phased treatment approach composed of twelve solutions is applied. Suppose the subject lacks the fundamental prerequisites, such as a permeable surface. In that case, proper land preparation solutions will be applied, and based on their ecological identity, they then receive the second phase’s applications. In conclusion, following the guidelines proposed in this paper, the decision-makers can treat urban voids to become more ecologically thriving and enhance their ecological performance.