<p>Single-phase concentrated solid solution alloys have physical and mechanical characteristics favorable for use as materials for multifunctional applications. Accurate knowledge of the thermal, magnetic properties and strain gauge sensitivity of the systems under study is important for obtaining new effective multifunctional materials with high practical performance. In this paper, we investigate the effect of composition changes in the CoCrFeNi system on important thermophysical and magnetic properties and strain gauge factors, namely heat capacity, coefficient of thermal expansion, thermal conductivity, magnetization, strain gauge sensitivity and electrical resistivity. By the example of five Co₂₀Cr₂₀Fe₃₀Ni₃₀, Co₂₀Cr₃₀Fe₃₀Ni₂₀, Co₃₀Cr₂₀Fe₂₀Ni₃₀, Co₃₀Cr₃₀Fe₂₀Ni₂₀, Co₂₀Cr₂₀Fe₂₀Ni₄₀ alloys temperature dependences of their thermophysical properties were considered, and the influence of the effects of structure on their behavior was discussed. The single-phase structure of all alloys was confirmed by XRD analysis, optical and scanning electron microscopy. An analysis of the behavior of magnetic and thermophysical properties, as well as indicators of strain gauges, allows us to conclude that single-phase high-entropy CoCrFeNi alloys can further become attractive systems for creating modern multifunctional materials for thermophysical, magnetic and strain gauge applications. The geometric factor is decisive in terms of the magnetization and Curie temperature values when considering the magnetic properties of CoCrFeNi alloys. The most attractive alloy from the point of view of strain gauge sensitivity is Co₃₀Cr₃₀Fe₂₀Ni₂₀ with a high content of chromium and cobalt.</p>