We recently reported a surfactant-free RT synthesis of Au NPs simply achieved using HAuCl4 as gold precursor, water as solvent, a mono-alcohol such as ethanol as source of the reducing agents, under slightly alkaline conditions, focusing on using LiOH as the base. As a result of that seminal parametric study and proof of concept performed over 350 experiments, it was established that the nature of the alcohol, the amount of alcohol (ethanol or methanol), the amount of base as well as the nature of cation in the base, all had an influence on the resulting size, morphology and stability of the NPs. An important pending point to address is how this synthesis compares with syntheses performed using other reducing agents. Glycerol is a green solvent more widely preferred to date to develop RT syntheses of Au NPs, and ethylene glycol (EG) has recently been introduced as an alternative to glycerol. We also anticipated that light could also have an influence on the resulting properties of the NPs obtained by these approaches. Clarifying the effect(s) the type of alcohol and the light used are much needed to (A) rationally select and tune experimental parameters, (B) to develop experimental setups for more reproducible syntheses, (C) to propose increasingly complex surfactant-free syntheses towards the synthesis of advanced materials, and to ultimately (D) develop greener NP syntheses via a better use of the resources and by minimizing the amount of waste generated in both the study but also the upscaling of the NPs. Here, we exploit the unique features of newly introduced surfactant-free syntheses to (i) relatively rapidly screen large parameter spaces without generating much waste to investigate the co-dependence of several experimental variables, (ii) compare in more details and clarify the pros and cons, similitudes and differences, in the use of selected mono-alcohols or polyols for the synthesis, (iii) establish the strong influence of light on the formation and the resulting optical properties, size or shape of the NPs in both mono-alcohols-and polyols-mediated syntheses. An overview of the parameters investigated is given in Figure .