While trying to find out the host-guest interactions the thrust has also been to make use of (1) an as much versatile software for the theoretical calculations (2) and a software which is also easily accessible for beginners that would enable them to learn the features of a software for theoretical (Quantum mechanics/ Molecular mechanics) Calculations. Such a report of the facts of investigation would put the beginners on the path for learning about the compromises required in a (macro-)molecular modeling. Typically the trade off between molecular sizes and available computer memory, together with the necessity to minimize the computational time (which could be a matter of computational costs). The computational chemistry package used for the current work is the online remote computational facility located at http://www.webmo.net . The strong point first of all is the simplicity of access and the student-proof way the web administration manages the Working Demo of this computational chemistry website. The second, but no less important is the fact that this working demo has one of the most advanced features for choosing the computational methods by providing several software engines with each one of them capable of being configured for several properties of molecules to be calculated. Computation, and the way the entire Job parameter can be archived in the resident disc for uploading into the Demo for subsequent calculations at any later time, and the way the results and job parameters can be exported to process and review in off-line mode are not features to which beginners can have access as readily as it is in this working Demo. There is no way as per the current version of the Demo to increase the computational time available per job to more than one minute. This provides an experience in choosing model systems for addressing specific theoretical queries even in the small molecule regime.

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