Precisely controlling the position of ionic groups along neutral polymer backbones in ionomers has led to novel nanoscale morphologies and promising properties, although the synthetic routes can be quite demanding. Here, we report a series of Li+-containing ionomers directly synthesized from step-growth polymerization of commercially available diol monomers (x = 6 or 12) and dianhydride monomers followed by neutralization with various amounts of lithium salts. The results are nearly precise linear polymers wherein nonpolar segments have precisely 6 or 12 methylene groups, as determined by the diol. The functional segment has two carboxylic acid pendant groups and 6-8 backbone atoms depending on the dianhydride addition. From X-ray scattering, these segmented ionomers exhibit well-defined nanostructures in contrast to the conventional random ionomers. The nearly precise nature of these segmented ionomers does not compromise the morphological ordering. The temperature-dependent ionic conductivities exhibit a systematic increase with Li(+ )neutralization level, as expected in a single-ion conductor. Notably, the ionic conductivities in these amorphous ionomers at high neutralization levels (>= 65%) exhibit Arrhenius behavior even at T > T-g, suggesting that ion mobility is decoupled from polymer segmental motion and largely within the aggregates; this finding could be a promising design strategy for solid polymer electrolytes. The synthetic scheme reported here provides a readily accessible suite of nearly precise ionomers by which to build fundamental correlations between polymer microstructures, nanoscale ionic aggregate morphologies, and ionic conductivities that are currently lacking.