Paradigms shift when solvent-less fluids come into play.

Solvent-less organic fluids are a new class of functional soft materials. Here the available fluid matrix makes it equally competitive with the solvent assisted systems. In this Perspective, the ways in which organic fluids challenge the established and accepted paradigms is highlighted. In general, fundamental properties such as photoisomerization, energy/electron transfer, photon upconversion and reversible dioxygen binding are controlled by solvents and/or solvent polarity, the presence of oxygen etc. Here solvent-less fluids challenge the paradigms by realizing it under neat, solvent-less and ambient conditions. This new phase of research has created many potential functional materials, which work better and more efficiently compared to the solvent assisted systems. Hence this relatively new research topic and the results need special attention. Here we discuss a few representative examples to point out the challenges offered in their functioning.