Index Exceeds Matrix Dimensions - Combining variables from different .mat files into one

Hello Again!

(I'm new to using structs and dir's so I apologize for all of the questions lately)

I'm trying to load .mat files from two different directories, and then pull variables from them to save into a new .mat file

Below is my current code:

function organizeData
%%Pull Data from relevant .mat files
eegDir = 'Unprocessed\'
eegData = dir([eegDir,'*.mat'])
for i = 1:numel(eegData)

eegName=eegData(i).name;

load (fullfile(eegDir,eegName))  
a=regexp(eegName,'_','split');
experimentName = a{1};

%%Pull Log Data from relevant .mat files
lDir = 'unprocessedLogs\'
logData = dir([lDir,'*.mat']);

for k = 1:numel(logData)
logName = logData(k).name;

if strcmp(logName, experimentName) == 1

load (fullfile(lDir,logName))

block(1).blue.participantID = r(1:5).blue.participant 
block(1).green.participantID= r(1:5).green.participant
block(2).blue.participantID = r(6:10).blue.participant

... more code

save_filename = (logName)
else
end
end
end

I'm trying to call r(1) - r(5)'s information to load into the new struct. Am I going about this wrong?

Thank you again for all of the continued help!

- Mary