Cellulose is a key biopolymer for advancing towards a more sustainable material economy. Leveraging its potential by controlling its chemistry, while adhering to the green chemistry principles is a challenging task. Within this work, we aimed at providing a new approach to this problem: by developing a green biobased reactivity promoter (BBIL-AcO), topped with in depth chemical characterization and fundamental understanding, we tried to build a new reaction design framework for the chemical modificaiton of cellulose under heterogenous conditions. Applying this knowledge on more complex cellulosic susbtrates (fibers, wood), led to novel material concepts like self-densified wood, transparent and stronger than aluminum, or record-breaking supercharged wood fibers for water remediaiton!