The 1-, 2-, and 3-dimensional structures obtained from conjugated rings of carbon atoms are reviewed. They
include finite small and large molecules (benzenoids, collarenes, beltenes, cyclacenes, cyclophenacenes, Möbius analogs, nanotori) and infinite macromolecules, nets and tilings (graphene, defected graphene, fractal benzenoids, nano-tubes,
nano-cones, etc.). A few challenges for future experimental work are also outlined.