Subplate neurons (SpNs) are among the earliest generated cortical neurons that form functional cortical synapses, and aid in cortical circuit development. A fraction of SpNs survive and form layer 6b in the adult cortex. While SpNs exhibit a large variety of molecular identities, it is unclear if molecular identity correlates with functional or connectomic identities and if different SpNs have similar developmental trajectories. To resolve these questions, we here characterize the functional intracortical circuits to molecularly identified subpopulations of SpNs with SpN-specific Cre-lines (CTGF-dgCre and Drd1-Cre) in