Ammonium zinc chloride (AZC) crystals doped with different strontium concentrations have been grown by the slow evaporation technique. Detailed temperature (300-450 K) and frequency (400-105 Hz) study of the dielectric constant (\varepsilon), loss factor (\tanδ) and the ac conductivity (σac) of the grown crystals has been carried out. Along the polar b-axis \varepsilon increased gradually with increasing temperature showing clear peaks at the phase transitions. Thermal recycling decreased \varepsilon, inhibited the peak height, decreased its broadening but without shifting the transition points. However, Sr2+-doping causes a shift of the transition temperature towards lower values and a decrease in the \varepsilon-peak broadening and height. Relation between 1/\varepsilon and T in the vicinity of the commensurate (C) to incommensurate (IC) phase transition revealed the validity of an equation similar to the Curie-Weiss law. Doping with Sr2+ in different concentrations causes a systematic change in the equation constants. Soliton pinning increased in the presence of Sr2+ leading to residual discommensurations (DC’s) in the C-phase. The dielectric constant decreased continually with increasing frequency for the undoped and Sr2+-doped samples. Doping with 0.144 wt% Sr2+ destroyed 25% of the C-phase, which means the possibility of having AZC crystal with reduced C-phase. σac increased with increasing frequency following a power law of the form σ=σo fs. Conduction by hopping was found to be dominant in all phases of AZC and after doping with Sr2+ in different concentrations. Mechanism for DC formation and annihilation was also discussed