Urban vacant land is often framed as a consequence of political and economic problems that negatively affect land values, tax bases, public safety, and community flourishing. At the same time, vacancy presents governments—and private developers—with opportunities for transformation. This commentary examines a development plan that makes use of vacancy in Chicago, Illinois to shed light on the ways in which vacancy can become a project in itself rather than a side effect of growth, decay, and change. I argue that through processes of erasure, re-inscription, and assemblage, vacancy projects enable redevelopment in ways that further politicians' and developers' agendas for post-industrial urban economic growth. In Chicago, vacant industrial land, such as the former Clybourn Corridor Planned Manufacturing District, is simultaneously positioned as an insurmountable problem and an exceptional development opportunity. I use the Clybourn Corridor case to illuminate the social, political, and economic processes through which vacancy is made productive in urban contexts. The relative opacity of such processes has profound implications for urban futures, shaping who makes plans for and benefits from the transformation of urban space. By delving into a vacancy project ethnographically in Chicago, a city struggling, like many, to define a post-industrial future, this commentary contributes to our understandings of vacancy as a tool to draw resources in and make development happen. It demonstrates the political, economic, and social processes through which urban land is defined and reconfigured as a site for public and private intervention as well as opportunity in the contemporary moment.