This project focusses on the use of the renewable, promising and abundant phenolic lignin biopolymer in the development of self-healing hydrogels with applications in the (bio)medical field. The pulping industry generates huge amounts of lignin as by-product, however, the majority is incinerated to recover bioenergy. Since lignin has a complex and yet not fully understood structure, it is not directly used as a high value reagent. To tackle this problem, in the first part of this research organosolv lignin will be valorised by mild catalytic reductive depolymerization in absence of external hydrogen gas to produce phenolic oligomers. The obtained products of this depolymerization step can have a wide variety of applications in e.g., resin synthesis and hydrogels. The depolymerized lignin will be characterized using several complementary techniques to obtain as much insight as possible in the lignin structure and properties. This oligomer mixture will further undergo hydroxyalkylation followed by reversible boronate ester formation to finally obtain a self-healing oligomeric lignin-based hydrogel. The properties of the hydrogels will be investigated in depth including the processability and self-healing ability. From the very start, the focus will be set on the sustainability of the applied chemistries via evaluation by the CHEM21 metrics toolkit. If needed, green alternatives will be evaluated to obtain a sustainable approach in the development of lignin-based hydrogels.