The title compound, [Co(C20H23N3O2)(C5H11N)](C24H20B) or [Co{(Me-sal)(2)dien}(pprdn)] BPh4, where (Me-sal) 2dien is 2,2'[1,1'-(3-azapentane-1,5-diyldinitrilo)diethylidyne]diphenolate and pprdn is piperidine, contains a pentadentate (Me-sal) 2dien ligand furnishing an N3O2 set, such that two of the N and one of the O atoms of the salicylidene rings define three positions of an equatorial plane, whereas the secondary amine N atom and the other O atom of the salicylidene lie in axial positions. The piperidine ligand occupies an equatorial position trans to one of the imine N atoms of the salicylidene. In the observed conformation of the pentadentate ligand, the salicylidene rings attain asymmetrical positions owing to the structural demands. The geometry of the resulting CoN4O2 coordination can be described as distorted octahedral. The asymetric unit contains two formula units.