We report the formation of zeolitic imidazolate framework glasses incorporating three organic linkers, from their corresponding novel crystalline structures [Zn(Im2-x-ybImxmbImy)]. Structure-property relationships between chemical compositions and thermal properties are analysed, in addition to the effect on the nanoscale porosity of the glasses formed. A probabilistic model is used to explain melting and the glass transition temperatures of the obtained glasses and link to the nanoscale structural disorder of their crystalline starting structures.