# How are electrons in conjugated molecules excited? [duplicate]

I have recently started reading about colour in organic molecules and come across conjugation of pi bonds. My question is pretty short... In transition metal ions I understand colour is caused by molecules jumping between the d sub orbitals as a result of ligand splitting them. The concept of excitation easily applies here. So what I want to know is. How do electrons get excited in a conjugated molecule?

In the case of conjugated organic compound, electrons jumps between $\pi$ and $\pi^{*}$ molecular orbitals happen to be within the visible light region. The key is the energy difference, the conjugation system has to be big enough or the energy gap between $\pi$ and $\pi^{*}$ molecular orbitals is too big and the wave length will be too short to be visible.