You asked for one of the most difficult properties to be predicted. Melting point is hard to be predicted for complex new synthesized compounds. The colour also you could predict it from experince (in the case of known structures) and maybe there exits some algorithms that i do not know...however the colour should be one of the last properties (in respect to the structure) you can look for in organic synthesis (this is what I belive). However please find below a site with software:
A free software program that you can download and gives a good prediction of several physicochemical properties (such as logP, logD, MW, HBDH, M_NO, TPSA and Ro5 violations) is Med Chem Designer.
You can find it here: http://www.simulations-plus.com/Products.aspx?grpID=1&cID&pID=25
Sometimes firms dealing with fine purity chemicals add or send to purchaser "demo" versions diskets dealing with properties of various chemicals supplied by them.
ChemDraw Ultra in the ChemBioOffice Suite 2012 allows you to draw any structure and show predicted Chemical Properties from the menu:- View/ Chemical Properties.
Selected Chemical properties from this window can be pasted below the entered structure. Color is not one of the properties.
You will have hard time predicting the melting point. This is one of the hard to predict property. You could try this tool to predict it with the well known Joback method:
Hello everyone, I was wondering for what kind of applications do we need such software and for what benefit? Have you heard about any use in the industry for example? Thanks for your help!
If the compound already exists you can find the most of the properties in the PubChem database. If the compound is novel, you can predict by ChemDraw, ChemSketch, or any other online tools.