  We apply the bootstrap kernel within time dependent density functional theory
to study one-dimensional chain of organic polymer poly-phenylene-vinylene and
molecular crystals of picene and pentacene. The behaviour of this kernel in the
presence and absence of local field effects is studied. The absorption spectra
of poly-phenylene-vinylene has a bound excitonic peak which is well reproduced
by the bootstrap kernel. Pentacene and picene, electronically similar
materials, have remarkably different excitonic physics which is also captured
properly by the bootstrap kernel. Inclusion of local-field effects dramatically
change the spectra for both picene and pentacene. We highlight the reason
behind this change. This also sheds light on the reasons behind the discrepancy
in results between two different previous Bethe-Salpeter calculations.
