As  the degree of conjugation increases
(i.e the number of electrons involved in the delocalized p-orbitals)
 the absorption energy decreases (> l, the energy between the ground and 
                                                           excited state decreases)
the absorption becomes more intense (>e, increased probability of absorption)
                    Benzene < Naphthalene < Anthracene < naphthacene < pentacene
 Abs. Max      262nm         275 nm             375 nm             475 nm            580 nm
   Log e              3.84             3.75                  3.90                  4.05                  4.20  
(Extinction)
Log
Extinction
Coefficient
             275 nm             375 nm              475nm absorption wavelength
Increasing the number of aromatic rings increases the absorption maximum
GM
Conjugation II