Since this is a business situation, if the colleague is a client, you would speak to him first and say "A, this is my boss, B". If he is a person in the company of lower rank than your boss, you would speak to your boss and say "Boss, this is Mr. A from the accounting department." Do not use the word "meet" and do not say "A, this is B", followed by "B, this is A". Just, "Jim Apple, this is my boss Joe Boss" if (Apple is a client) OR, "Joe Boss, this is Jim Apple from Accounting." CAUTION: This is my memory of the proper form of introduction from my class on Manners at Penn State, many years ago. It is for purposes of discussion only and should not be relied upon for any poster for any reason. In other words, if you screw up and get fired, don't blame me.