This contribution describes the synthesis of 3-nalkyl-1-vinylimidazolium bromide ionic liquid monomers (ILMs), ion exchange with bis(trifluoromethane)sulfonimide anion (NTf2-), and their radical polymerization to a homologous series of poly(ionic liquid)s (PILs) containing an imidazolium ion substituted with alkyl chains of different lengths (C2(n=7-11)). Owing to the presence of a long alkyl chain, all the ILMs show crystalline phases whose melting point and melting enthalpy increase sharply with increasing alkyl chain length, and those parameters decrease upon replacing Br- with a NTf2- anion. In addition to the solid crystalline phase, the ILMs with a Br- ion only show liquid crystalline mesophases above the melting of solid crystals. The corresponding PILs are semicrystalline in nature due to crystallizable alkyl side chain showing similar chain length and counteranion-dependent melting behaviors with poor crystallinity compared to those of ILMs. The formation of strong birefringent crystals of various morphologies including Maltese-cross and ring-banded spherulites is observed for ILMs. However, the corresponding PILs with a Br- ion show crystals with fibrillar morphology with weak birefringence, but surprisingly such fibrils are not observed for PILs with a NTf2- ion. The influence of structural modulations of ILMs and their corresponding PILs on their ionic conductivities is also investigated. Moreover, PILs with a Br- ion exhibit an upper critical solution temperature (UCST)-type turbid-to- transparent phase transition in CHCl3 with tunable cloud point as observed from turbidity and calorimetric measurements. Such a thermoresponsive solution phase behavior is totally absent for PILs when Br- is replaced with a NTf2- ion.