We analyzed the relationship between exploration-oriented and exploration-oriented alliances. Through the complementarity approach, three possible relationships were analyzed: complementarity, substitutability, and no relationship. We use Technological Innovation Panel data for Spanish manufacturing firms for 2005–2013. The econometric technique that we used to estimate the coefficients was population-averaged OLS. Our findings suggest that alliance portfolios formed by exploration-oriented and exploration-oriented alliances achieve worse innovation performance than specialized exploration or exploitation portfolios. In addition, we found that a single class of alliance has different impacts on innovation performance depending on whether it is implemented by a young company or a mature company.