Investigations on gold and gold-zinc oxide nanocrystals encapsulated in a matrix of a metal-organic framework (ZIF-8) upon plasmonic heating with nanosecond laser pulses are presented. Irradiation of Au@ZIF-8 composite particles leads to heating of the gold core and decomposition of surrounding matrix acting as temperature probe. Cavities inside the ZIF-8 matrix are found on TEM images after irradiation. Their size is determined dependent on laser energy density and the generated heat at the gold core after absorption of a laser pulse approximated. The surrounding of the gold cores can be heated up to ZIF-8 decomposition over a distance up to 60 nm. This represents a method to visualize heat transfer from the gold cores to the ZIF-8 matrix in three dimensions. Studies on ZIF-8 encapsulated Au@ZnO dot-rod particles give insight in heat transfer between the particle components and show the applicability of the method to different, more complex systems. © 2022 The Authors. ChemNanoMat published by Wiley-VCH GmbH.