Conjugation and UV

The more conjugated a compound is, the lower the energy of the LUMO->HOMO transition:

As more double bonds are conjugated, the absorbed wavelength enters the visible region of the electromagnetic spectrum. This is why most colored organic molecules are long and conjugated. A minimum of 8 double bonds are required to dip into the visible region.

That is assuming the alkene has no heteroatoms. See if you can explain the apparent paradox below:

The solution is in the orbital hybridization. In the former, the sp² nitrogen has its lone pair pointing perpendicular to the pi bonds, so it cannot overlap/conjugate. While in the latter they are in the same plane.

In addition, the latter has an n -> pi* transition rather than a pi -> pi* transition. I'm unsure why the n->pi* transition requires both orbitals to be in the same plane.