Recognizing the value of including complex pyridines in small-molecule screening collections, we developed a previously unexplored [2+ 2+ 2]-cycloaddition of silyl-tethered diynes with nitriles. The tether provides high regioselectivity, while the solvent THF allows catalytic CpCo (CO) 2 to be used without exogenous irradiation. One of the resulting bicyclic and monocyclic (desilylated) pyridines was identified as an inhibitor of neuregulin- ...