Small carbon clusters are present in flames and discharges, and in interstellar space. Although buckminsterfullerene (C60) is well characterised, far less is known about` smaller carbon clusters, which tend to progressively adopt structures as chains, rings, bi-rings, and fullerenes. To learn more about carbon clusters we have measured electronic and infrared spectra for clusters of different sizes and isomeric structures. To avoid isomeric ambiguities, we have adopted a strategy whereby the target isomer (linear, ring, bi-ring, or fullerene) is preselected using tandem ion-mobility and mass spectrometer stages, prior to spectroscopic interrogation with beams of tunable light in a cryogenically cooled ion trap. Prominent electronic transitions of charged cyclocarbons (cations and anions) are found to occur in the visible and near-IR spectral regions, with a progressive, regular shift of the main bands to longer wavelength with increasing ring size. The C4n+ rings possess extraordinarily sharp, intense IR transitions that are at least 50 times stronger than transitions of the corresponding bi-ring and fullerene isomers, and which are associated with a single vibrational mode that propels charge back and forth across the ring. The intense vibrational transitions may serve as a signature for the presence of carbon rings in remote or hostile environments and may also provide a means for energised rings to dissipate energy through IR emission.