A template-free benign approach to modify polypyrrole (PPy) with bioinspired catechol derivatives dopamine (DA), 1,2-dihydroxybenzene or catechol (CA), and L-3,4-dihydroxyphenylalanine (DOPA) is reported. It is found that PPy functionalized with these catechol derivatives (DA, CA, and DOPA) exhibited fibrous structure, smaller particle size, good water dispersibility, and enhanced film adhesion. Surprisingly, it is found that adding a small amount of catechols can also improve PPy's electrical conductivity. This rapid, one-step, in situ, template-free method provided an alternative strategy to the facile production of PPy fibers. Among these three catechols, functionalized PPy and DA-PPy exhibits the smallest particle size and best performance in both adhesion and electrical conductivity. In contrast, the control phenylethlamine (PA) modification had almost negligible influence on the PPy properties, which provides strong evidence that instead of amine functional group or coexistence of both catechol and amine moieties, catechol itself is responsible for the successful functionalization of PPy and overall performance improvement. Furthermore, catechol-PPy nanofibers are blended into polyvinyl alcohol (PVA) aqueous solution and casted to form thin films; as-synthesized conductive films are found able to bond strongly onto the surface and may find broad applications in manufacturing biosensors and electronic devices.