Alejandro L. answered 10/12/16
Chemistry tutor (all areas) + Intro Astronomy
Very few molecules have visible emission spectra. In general these molecules must be composed of an extended conjugated chain (aromatics and polyenes) or contain elements for which decay can occur via spin cross-over, where flipping of the electron spin occurs leading to a spin forbidden transition of lower energy (e.g. lanthanides).
In general, the energy of the photon emitted will be lower than that of the photon absorbed due to various modes of decay that can occur in a molecule (rotational, vibrational, etc.). What this means is that if a molecule emits visible wavelengths of light (green --> red) it must absorb at the very least violet -->green photons in order to emit light. If this is the case then you have both absorbance and emission contributing to the overall color of a substance.
On the other hand, if the compound requires higher energy photons to emit light then it will not absorb visible light and any color associated with the compound will be due to emission.
As a rule of thumb, most compounds you'll encounter in live will yield color because of absorbance and not emission. The obvious exception being those where high inputs of energy are supplied to provide color: TV and computer monitors and neon lamps, to name a few.