I already know that thymolphthalein is soluble in alcohols, very alkaline aqueous solutions, acetone, and propylene glycol methyl ether. My questions are what other solvents dissolve thymolphthalein, and what additives increase solubility (for example, specific surfactants)?
One expects [poly(ethylene oxide)-co-(polypropylene oxide)-co-poly(ethylene oxide)] triblock surfactants will micellize it (e.g., Pluronics); possibly Tergitols. It looks too bulky to fit inside even gamma-cyclodextrin.
Hang a suitable side chain off the phthalic anyhydride and the product will dissolve in pretty much anything. What does pH mean outside water?