This work is focused on investigating the effects of relative amounts of lignin and cellulose contents of bio-fillers on mechanical properties and moisture reluctance of PRC (particle reinforced composites). FTIR (Fourier- Transform Infra-red) spectroscopy was used to identify the cross-links and hydrogen bonds (H-bonds) and determine their densities in different PRCs. It was found that the relative amount of lignin-cellulose influenced the cross-link and hydrogen bond densities due to difference in their chemical structures. Filler size and packing density are other factors. Usually, cellulose is embedded in the lignin and hence presence of higher lignin overshadowed the characteristics of cellulose and prevents it from establishing bonds with matrix. The influence on mechanical properties was investigated through flexural and charpy impact tests. And finally moisture reluctance of different PRCs was determined and found that those with higher lignin fillers and those with completely impregnable fillers were highly reluctant to moisture absorption.