We propose to use a neutral electrolyte based on an aqueous solution of NaCl instead of commonly used aggressive acids or alkaline electrolytes for the purpose of electrochemical nanostructuring of GaAs and CdSe substrates. It is shown that the process of material porosification can be controlled by the conditions of anodic etching. A photoluminescence analysis of the porous structures obtained and referenced to the as-grown substrate demonstrates that an effective passivation of the surface occurs during anodization in this electrolyte. The results obtained pave the way for the development of optoelectronic devices based on electrochemically nanostructured GaAs and CdSe compounds, particularly for high-efficiency solar cells.