Solution properties of an ionomer, poly(2-acrylamido-2-methyl-1-propanesulfonic acid-co-styrene) (PAMPST) with a 95 mol % styrene content, are investigated by using size exclusion chromatography (SEC) coupled with differential refractive index (RI) and multiangle light scattering (MALS) detectors and steady-state fluorescence measurements. Dimensions of ionomers in solution depend on the polarity of the solvent that modifies the interactions of the ionic groups. Measurements were performed in two solvents of very different dielectric constant, namely tetrahydrofuran (THF) and dimethylformamide (DMF), and the addition of a low molecular weight electrolyte such as LiCl to both solvents clearly improves the results affording scaling laws and unperturbed dimensions. In spite of the different thermodynamic quality of the solvents DMF and THF solutions, the extrapolations to unperturbed dimensions provide similar values of the characteristic ratio C-n = 11-12. However excimer-to-monomer emission intensity ratios, as consequence of the different origin of excimers, substantially depend on the solvent THF/DMF composition. Molecular dynamics simulations performed on oligomers of PAMPST in THF, THF + LiCl, DMF, and DMF + LiCl solvents support the conclusions obtained from experimental measurements.