Smart Tags are functional elements that transmit information and combine 2D barcodes with environmental sensors. They can be applied to products, such as packages, in an economical way without significantly increasing the price of the product. One important feature of Smart Tags is that they can be applied to products on high-speed conveyor belts, making them suitable for use with various consumer goods. These tags are sensitive to environmental conditions and can be unique, allowing them to provide services with respect to a given context. In the context of mobile devices, a Smart Tag is a small wireless device that can be attached to physical objects and trigger actions or provide information when it is in the vicinity of a smartphone or other device. Smart Tags have a variety of applications, including inventory management, location tracking, and security. The technologies that enable these smart labels include 2D barcodes, functional inks such as thermochromic and photochromic inks, and printed visual indicators. This paper deals with the printing of 2D codes using thermochromic inks with different activation temperatures (TA) by screen printing technique. The printed 2D codes will be exposed to a defined temperature range around TA and read by scanning with a mobile phone. The colorimetric properties of thermochromic inks will also be measured within this temperature range. The aim of this paper is to determine the temperature range in which a certain thermochromic ink results in readable 2D codes.