Mixed-use development is increasingly popular in land use planning and zoning, fostering a combination of residential, commercial, and cultural uses into one space. However, there is a lack of understanding of the vertical mix office space within a high-rise commercial building and the dynamics of the industry mix between buildings. This paper examines the spatiotemporal patterns of industry mix between and within office buildings in Sydney CBD from 2006 to 2017, using the data obtained from the City of Sydney floor space and employment surveys. This is the first study that identifies the dynamics of an industrial ecosystem in central Sydney, which has transformed to homophily land blocks, with increasing vertically heterogeneous office buildings, over the past decade. In addition, the study found that the significant clustering of anchor tenants, such as finances, hospitalities, and knowledge-based industries, are apparent.