The diversity of synapse-organizing molecules opens up tremendous cooperative potential, yet the extent to which this is utilized is incompletely understood. We now report in Nature Communications that the postsynaptic adhesion proteins LRRTM1 and SynCAM 1 act together in the prefrontal cortex to control synaptic connectivity. Our results show that the functional cooperation of synapse-organizing proteins can profoundly expand their individual roles across synaptic, network, and behavioral domains. Congratulations to the shared first authors, Karen, Adema, Dhruba, and Katie! This was a strong team effort, bringing together a range of complementary approaches to address how synapse-organizing mechanisms work together. DOI 10.1038/s41467-023-36042-w