 Self-assembly techniques have become increasingly popular for fabricating porous films with adjustable porosity and high structural consistency. These films can be used as interference substrates for label-free biosensing applications. Recent advances in this field include the use of ordered porous colloidal crystals, OPCC, for biosensor applications. OPCC films are made using self-assembly techniques, which is the bottom-up approach. They offer several advantages over other porous films, including budget cost, adjustable porosity, and high structural consistency. This review will first introduce the fundamental components of self-assembling materials and then discuss various self-assembly techniques in detail. It will also summarize recent studies that use the OPCC technique for label-free biosensing applications and divide them into several aspects for further discussion. Finally, it will evaluate the strengths and weaknesses of self-assembly techniques and discuss potential future research directions. This article was authored by Asian One and Weiping Chen. We are article.tv, links in the description below.