The union of functionalized pyrroloindolizines for the synthesis of heterodimeric products relevant to myrmicarin alkaloids is described. Design and synthesis of tricyclic substrates and new methods for their union enable the investigation of late-stage cyclopentannulation strategies. The rapid assembly of dimeric structures using unique modes of pyrroloindolizine reactivity presents a concise approach to the dimeric myrmicarins and relevant derivatives.