Supposingly, managers allocate their attention through knowledge structures favouring signals that connect with existing knowledge. However, this top-down attention allocation leaves open how managers detect and pursue opportunities for exploratory innovations which require novel knowledge. Our study aims to measure instances of the opposing attention mode, i.e., bottom-up allocation, and provide evidence for its implications for firm’s exploratory innovations. We conduct this analysis in a setting where firms source input bottom-up from alliance portfolios. Our sample comprises of 223 firms from the German cooperative banking sector and 112 board members. We obtain alliance data from an industry survey and extract innovation information from bank’s financial statements. We measure manager’s bottom-up attention allocation through their attention variety on a professional social media platform. Conducting poisson regressions, our results indicate that bottom-up attention allocation can significantly promote exploratory innovations. This is particularly true for alliances with high knowledge distance and high managerial attention variety. We contribute to the nascent literature on competing managerial attention modes and their implications for firm performance. We show that managers can deliberately influence their attention variety through social media and ultimately increase exploratory innovation returns from a diverse alliance portfolio substantially.