We report on the formation of single poly(N-vinylcarbazole) (PVCz) chains in one-dimensional channels of [La(1,3,5-benzenetrisbenzoate)](n), where the side carbazolyl groups of the confined PVCz are effectively pi-stacked. This ideal conformation of PVCz chains in the coordination nanochannels contributed to a drastic increase in hole mobility, which was 5 orders of magnitude higher than that in the bulk state. It is also noteworthy that PVCz isolated from the nanchannels still had a high hole mobility.