Using a bio-inspired cellulose template, new charge transfer (CT) nanoparticles (NPs) with unique and intriguing emission properties are reported. Pyrene-modified 2,3-di-O-methyl cellulose formed CT complexes with small molecule acceptors, e.g. 7,7,8,8-tetracyanoquinodimethane (TCNQ), and exhibited aggregation-induced emission (AIE) in aqueous medium upon nanoparticle formation. The TCNQ-CT NPs showed multicolor fluorescence emissions at 370-400 nm, 602 nm and 777 nm, when excited at 330 nm, 485 nm and 620 nm respectively. The cellulose-TCNQ NPs are biocompatible and demonstrate an advance in the use of the CT mechanism for biomedical imaging applications both in vitro and in vivo.