Tips for my trip to Zurich

Warning: Zürich is expensive, the most expensive city in one of the most expensive countries in Europe. I hope your wife's employers are covering her expenses.

For the weekend, I vote Paris. Because there is more to see. You can get a train, city centre to city centre, in 4 hours. This will be as quick as flying (if you add in all the time to get to and from the airport, check-in etc.), and a lot more comfortable.
Website for the company running the trains: https://www.tgv-lyria.com/en-CH
The last train leaves Zürich HB (main station) at 17:34, arrive Paris Gare de Lyon 21:37. So if you can catch that train on Friday night and find a hotel within walking distance of Gare de Lyon, you get the whole of Saturday and can get a late train back from Paris on Sunday. Full timetable here: https://www.tgv-lyria.com/sites/default/files/pdf/BROCHURES_CO/lyria-timetable-france_switzerland-07.07.18_08.12.18-en.pdf

"Interlaken, Lauterbrunnen and Grindelwand" - These are good for your other weekend. Pick one place to stay in, and visit the others (connecting trains and cable cars). Website with hotels and info about the area: https://jungfrauregion.swiss/en/summer/
Zürich to Grindelwald is 2½ hours by train.

I also suggest Luzern. Only 60 minutes from Zürich by train. You can do an evening visit, or you can go on your own during the day.

It is very easy to get around Switzerland by train, tours are not needed. Here is a map of Swiss railways which may help: https://www.sbb.ch/content/dam/sbb/de/infotexte/uebersichtskarte-sts.pdf

P.S., just checking. As Indian citizens, you know you will both need visas? This is a so-called "Schengen Visa". You need to apply to your local Swiss embassy or consulate (I imagine your wife's employers will have organised her visa). This visa is valid for all countries surrounding Switzerland, including France and Italy, so no problem crossing borders.

Thanks a lot for your quick response and the heads up for the cost, yes her expenses are all taken care by her employer.
Thank you for all the suggestions, you have got me sorted now.
Just few quick questions, how safe is it to roam around in nights, till 9 or 10 PM ? Anything that i should be careful about other than normal vigilance

Yes, she has already received her Visa and I am in process of getting mine.
Thanks again for the help and suggestions.

If you like art museums, the Kunsthaus in Zurich is very much worth visiting.

Yes, it is perfectly safe to roam around at night. In the summer, life happens on the streets. Most of Zürich city centre, and other Swiss cities, is pedestrianised in the centre. Lots of restaurants with outside tables on the pavement, full of people. Plus people wandering around the streets, on Friday and Saturday night until well past midnight. On those two nights there are night buses, after midnight, to get people home.

Great !! Thank you for all you suggestions !!

Looking forward to explore some local cuisine and taste some good brewed beers on streets..!!

I would focus on Switzerland the whole time. One weekend head to the
Berner Oberland, the other fo to Lucerne. Take advantage of being close to these beautiful destinations.

Thank you for suggestions Suki !! I have just taken a trip to one of the most serene places, Leh and Ladakh through road trip. Hence i want to have a mix of city and beauty together !!