In this paper, two pairs of complementors have to decide whether to merge and eventually bundle their products. Depending on the degree of competitive pressure in the market, either both pairs decide to merge (with or without bundling), or only one pair merges and bundles, while rivals remain independent. The latter case can very harmful for consumers as it brings surge in prices. We also consider the case in which one pair moves first. Interestingly, we find a parametric region where first movers merge but refrain from bundling, to not induce rivals to merge as well.