Manganese-mercury thiocyanate, MnHg(SCN)(4), crystal is considered to be an important organometallic nonlinear optical (NLO) material exhibiting higher thermal stability and second harmonic generation (SHG) efficiency. In order to understand the effect of Ca2+ as an impurity on the physicochemical properties, we have grown pure and Ca2+ doped (with a concentration of 1 mol%) MnHg(SCN)(4) single crystals by the free evaporation of solvent method and characterized structurally, chemically, optically and electrically by adopting the available standard methods. Results obtained indicate that Ca2+ doping increases significantly the optical transmittance, SHG efficiency, and DC electrical conductivity and decreases the dielectric loss factor (improves the crystal quality), and AC electrical conductivity without distorting the crystal structure. Also, the low dielectric constant (er) values observed for both the pure and doped crystals considered at near ambient temperatures indicate the possibility of using these crystals not only as potential NLO materials (useful in the photonics industry) but also as promising low er value dielectric materials (useful in the microelectronics industry). (C) 2018 Elsevier B.V. All rights reserved.