The relevance of relatedness on economic development in space has been intensively studied. In this joint publication (pdf) with Sandor Juhasz and Ron Boschma in Papers in Regional Science, we switch the perspective and study the impact of geography & complexity on relatedness. Using patent data, we find expertise in different technologies being concentrated in the same region(s) increases chances of these technologies becoming complements and eventually related. Complex technologies are less likely to increase their relatedness over time. However, once complex technologies are related, further complementarities and similarities are likely to evolve. Hence, the paper links ideas on complexity, relatedness, and #geography and empirically confirms their co-evolutionary nature. This is crucial for technology and innovation policy, as it calls for a stronger consideration of geography and complexity in their design. In addition, our results discourage policies supporting individual technologies.